on the structure and ferments of the digestive organs of ......the digestive apparatus of scorpions...

On the Structure and Ferments of the DigestiveOrgans of Scorpions.

By

E. N. Pavlovsky, M.D., D.Sc,

Professor at the Military Academy of Medicine, Leningrad,

and

E. J. Zarin. M.Phar.,Professor at the University of Latvia, Riga.

With Plates 22 and 23 and 7 Text-figures.

1. STRUCTURE OF THE DIGESTIVE ORGANS IN THE

SCORPION.

ONE of the authors of the present investigation has already-published certain data on the structure of the digestiveapparatus in scorpions (Pavlovsky 1, 1917). Of these dataonly those appear here which have some bearing on the explana-tion of the function of the digestive organs. The details ofpurely morphological character are omitted. It is also notnecessary to make a detailed review of the anatomical litera-ture ; the necessary data will be referred to in the correspondingparts of the text.

The digestive apparatus of scorpions consists of the followingparts : (A) pre-oral cavity ; (B) fore-gut, (a) mouth opening,(b) pharynx with sucking apparatus, (c) oesophagus, and(d) post-cerebral sucking apparatus; (C) mid-gut, (a) stomach,(b) hepatic portion of the intestine, (c) ileum, (d) stomachgland, and (e) liver ; and (D) hind-gut with the anal aperturein the soft articulation membrane connecting the poison sacwith the ultimate segment of the body.

NO. 278 Q

222 E. N. PAVLOVSKY AND E. J . ZARIN

A. The P r o - O r a l C a v i t y .

The pre-oral cavity in the scorpion is limited above by thechelicerae (Text-fig. 1, C), on the sides by the coxal joints ofthe pedipalpi (P), and below by two pairs of maxillary appen-dages of the first and second pairs of legs (M), overlapping eachother, the appendages of the first pair lying above and laterally

TEXT-FIG. 1.

MVejovxs c r i s t i r n a n u s . Jfre-oral cavity; lateral view after

removal of coxal joint of right pedipalp. Low power.1

to the appendages of the second pair of legs. On the posteriorwall of the cavity the rostrum protrudes (Text-fig. 1, R, 7, r;PI. 22, fig. 3, r). Above the chelicerae the anterior margin of thecephalothorax is projected.

Their form is in general filleted with a flattened mediansurface. The chitin of the chelicerae is perforated by numerouscanals, which are present in large numbers in its thickestportions. The inferior and median surfaces of the chelicerae

1 For lettering of text-figures see p. 258.

DIGESTIVE ORGANS OF SCORPIONS 223

are covered with a dense brush of long dentate hairs (dermato-chaetae plerothaecatae, Pavlovsky 1, 2a, 1917, 1924), from thebase of which canals filled up with the protoplasm of the hypo-dermal cells are given off into the chitin. The hypodermis forms

TEXT-FIG. 2.

Heterometrus indicus. Stomach (vt) and stomach glands ofembryo with fully formed body. Low power.

TEXT-FIG. 3.

Hemisoorpius lepturus. Stomach gland of adult. Low power.

on the inner and inferior surfaces of the distended joint of thechelicerae three longitudinal thickenings ( = ' couche glanduleuse'of spiders). The pedipalpi take part in the formation of thepre-oral cavity only with their coxal joints, the concave mediansurface of which bears a dense hairy cushion of soft chitin.The edges of this surface are sharply ridged and covered withthick setae. The hypodermis of the coxal joints of the pedipalpi

224 E. N. PAVLOVSKY AND E. J . ZAEIN

consists on the upper wall of cylindrical epithelium, whilst inthe other parts the epithelium is flat. Neither the cheliceraenor the coxal joints of the pedipalpi bear any glands, in whichrespect the scorpions.differ sharply from spiders, the cheliceraeof which enclose the poison glands (for literature see Pav-lovsky, 2, 1912) and the basal joint of the maxillae of which

TEXT-FIG. 4.

oa

Scorp iops p e t e r s i . Anal aperture with covering chitinousplates in the articulatory membrane between the poison vesicleand last segment of pre-abdomen.

encloses the salivary glands (Schimkewitsch, 3,1884; Bertkau,4, 1885 ; Gaubert, 5, 1892).

The first pair of maxillary appendages are covered on themedian surface with numerous dense hairs with a thick layerof hypodermis underneath them. In the cavity of the appen-dages of all scorpions there is an inferior-median group ofsimple alveolar glands opening by special pores into the chitin(MacLeod, 1884 ; PI. 22, fig. 1, lmav gs ; PI. 23, fig. 26, gs).In the pullus of H e t e r o m e t r u s c y a n e u s Pavlovsky(1,1917) found also a second group of smaller and less numerousglands of a similar character lying near the median edge of theappendage. The maxillary appendages of the second pair oflegs are separated, therefore the name lower lip (Gaubert,

DIGESTJVE ORGANS OF SCORPIONS . 225

5, 1892) is not applicable in this case. Their lower surface iscovered with the same kind of chitin as the remaining partsof the body, whereas the lateral and upper parts are coveredwith soft chitin bearing numerous dense hairs (dermatochaetaeathaecatae). The supero-lateral surface of each appendagebears a longitudinal groove (PL 22, fig. 1, lma2), on the sidesof which the chitin is of an undulating nature owing to thepresence of fan-shaped outgrowths of the external cuticle.The hypodermis of the part of the appendage described iscomposed of very tall epithelium disposed in many layers.In its cavity are also found maxillary glands concentrated inthe posterior part of the appendage on the supero-exteriorsurface of which they open (PI. 23, fig. 26, Ima, gs).

The rostrum (PL 22, figs. 3-8, r ; Text-fig. 1, B, 7, r), whichis of various forms in different scorpions (Pavlovsky, 1, 1917,pp. 58-9), is in the form of a keeled evagination between thecoxal joints of the pedipalpi, its upper margin entering in theslit between the chelicerae. The rostrum is covered externallywith soft and hairy chitin of the same character as on thepedipalpal cushions. The folds of the teguments of the superiorand lateral surfaces of the rostrum do not bear a glandularcharacter. In the interior of it are several muscles, amongstwhich we may distinguish the following : (1) the proper rostralmuscles and (2) muscles connected both with the rostrum andthe pharyngeal sucking apparatus. To the proper rostralmuscles are referred the following: (a) m. t r a n s ve r susr o s t r i maximus(6) , (PL 22, figs. 3-7, ml39), (b) m. t r a n s -ve r sus r o s t r i d i f fusus (7), (PL 22, figs. 3-6, ml3S), and(c) m. o b l i q u u s r o s t r i v e n t r a l i s (PL 22, figs. 3, 7, 8,ml43). The first two muscles cause the rostrum to attenuateon contracting, whilst the last-named paired muscle shortensthe lower half of the rostrum in the antero-posterior direction,and in this way allows a freer access to the oral opening. Therostro-pharyngeal muscles are represented by (a) m m . r o s -t r o - p h a r y n g e a l e s s u p e r i o r e s (PL 22,fig. 3, mliO) (fromthe pharynx to the upper wall of the rostrum), (b) m m . r o s t r o -pha ryng . ea l e s i n f e r i o r e s l a t e r a l e s (P1.22,fig.8,ml41),

226 E. N. PAVLOVSKY AND B. J . ZARIN

and (c) mm. r o s t r o - p h a r y n g e a l e s infer ioresmediales (PI. 22, fig. 3, ml42) (from the lower part of therostrum to the pharynx). These muscles either dilate thepharynx or draw backwards, upwards, and inwards the inferiorsurface of the rostrum (for particulars concerning the muscula-ture of the rostrum see Pavlovsky, 1, 1917, pp. 60-2).

B. The P o r e - G u t .

(a) The mouth is situated between the inferior extremityof the base of the rostrum, the coxal appendages of the firstpair of legs converging at this point, and the adjoining partsof the coxal joints of the pedipalpi (Text-fig. 1, 06 ; PI. 22,fig. 3, ob).

(b) The pharynx is dilated into a pharyngeal chamber(sucking apparatus) lying between the base of the rostrumand the anterior surface of the cerebral ganglia (Text-fig. 7 ;PI. 22, fig. 3, ph). It is lined inside with a thick chitinouscuticle perforated by pores (gustatory pores ?) ; underneaththe cuticle lies a layer of epithelial cells. The sucking apparatusof the pharynx is provided with numerous muscles (8) whichcan be referred to two groups—dilatators and sphincters.To the former belong: (1) m. d i l a t a t o r p h a r y n g i sl a t e r a l i s (Text-figs. 6, 7 ; PI. 22, figs. 3, 4, m99, from thelateral walls of the pharynx to the alae of the pre-oral ento-sclerite), (2) mm. r o s t r o - p h a r y n g e a l e s i n fe r io re s(PI. 22, figs. 3, 8, mUl,mU2), (3) mm. r o s t r o - p h a r y n -geales supe r io re s (PI. 22, figs. 3, 5, ml40), (4) m.d i l a t a t o r p h a r y n g i s s u p r a r o s t r a l i s in fe r ior (PI. 22,fig. 3, m9S, from the pharynx to a point above the base of therostrum), (5) m. d i l a t a t o r p h a r y n g i s s u p r a r o s -t r a l i s supe r io r (Text-fig. 7, ml44, a paired muscle-bandextending from the upper point of the pharynx to the pointat which the anterior wall of the cephalothorax passes fromthe horizontal to the vertical plane).

The sphincters of the pharynx (Text-fig. 7, ml30 ; PI. 22,figs. 3-5, 8, ml30, ml30a) are represented by muscle-bundlesstretched between the protruding ridges of the pharynx and

DIGESTIVE ORGANS OF SCORPIONS

TEXT-IMG. 5.

227

f I

•un—\

Diagram of the digestive organs of scorpions. Ventriculo-intestinalcanal with the appendages and the heart with dorsal aorta (ao)on it in C e n t r u m s (the massive liver is seen above).


TEXT-FIG. 6.

m.

1MI-

Cephalothoracio and pre-abdominal portions of the intestine afterremoval of stomach gland and liver. The hepatic ducts andmalpighian vessels are visible. In the sucking apparatus of thepharynx (ph) and oesophagus (ore) only part of the muscles arerepresented.

DIGESTIVE OEGANS OF SCORPIONS 229

TEXT-FIG. 7.

Fore- and hind-guts of scorpion with their respective muscles.The upper part of Text-fig. 7 corresponds to the part of Text-fig. 6anterior to the diaphragm (d) depicted laterally. The pharyngealsucking apparatus with dilatators (m99) running from the wings ofthe pre-oral entosclerite (en) and the post-cerebral suckingapparatus (us) are visible. The lower part of the figure representsthe hind-gut with m. l e v a t o r ani (ml48) and the anal papillae(pa) extruded outwards.

230 B. N. PAVLOVSKY AND E. J . ZAEIN

alternating with the bundles of m. d i l a t a t o r p h a r y n g i s1 a t e r a 1 i s (for comparison of the musculature of the suckingapparatus of scorpion and other Arachnids see Pavlovsky,1907, pp. 60-6).

(c) The oesophagus represents a thin tube passing throughthe pharyngeal nerve-ring (Text-fig. 7, oc, era). Its innerlumen is stellate, owing to the presence of the longitudinalfolds of the epithelium (PL 22, figs. 9-11). Exteriorly to theoesophagus there is a layer of circular muscle-fibres. Furtherbackwards the epithelium widens and assumes an oval formin section. To the muscular membrane are admixed longitu-dinal fibres acting as supporters of the oesophageal walls.

(d) The post-cerebral sucking apparatus. To the post-cerebral portion of the oesophagus are attached m m . d i l a t a -t o r e s o e s o p h a g i r e t r o c e r e b r a l e s l a t e r a l e s (Text-fig. 7 ; PL 23, fig. 20, ml45, from the oesophagus to the anteriorprocesses of the endosternite) and mm. d i l a t a t o r e so e s o p h a g i r e t r o c e r e b r a l e s r a d i a l e s {ml46, ml46a,from the lateral and superior surfaces of the oesophagus tothe sides ; the ends of the muscle-bundles are lost betweenthe lobules of the digestive gland). Their antagonist is repre-sented by a sphincter of the sucking apparatus in the form ofcircular muscle-fibres (ml47', Text-fig. 7, us).

Immediately behind the sucking apparatus is situated afillet of epithelium bordering between the fore- and mid-gut.

C. The M i d - g u t a n d i t s A p p e n d a g e s .(a) The stomach represents the part of the mid-gut lying in

the cephalothorax between the border fillet and the diaphragm.It is lined inside with cylindrical epithelium (PL 22, figs. 1'4,15, z) of the same character as in the digestive glands. Itsepithelium consists of irregularly alternating ferment cells andcells absorbing the nutritive substances. The epithelial liningof the intestine rests on the membrana propria, exteriorly towhich is situated a fillet of epithelium bordering between thefore- and mid-gut.

The stomach is dilated in the embryos of H e t e r o r n e t r u s


c y a n e u s (Text-fig. 2, vt), and in its pulli previously to theirmoult it carries rudimentary ventral processes (PI. 22, fig. 15 ;PI. 28, fig. 21, do).

(b, c) The intestinum tenuum (Text-figs. 5, 6, 7, im) lying inthe pre- and post-abdomen of the scorpion may be divided intotwo parts : (1) pars tecta, s. hepatica covered by the liver(this part occupies the pre-abdomen, the first and sometimesalso part of the second post-abdominal segment (Text-figs. 6,7, im) ; (2) pars nuda, s. ileum running in the post-abdomen toits last segment in which it unites with the hind-gut (Text-fig. 5, im). The diameter of the intestine is not great ; in theileum it is somewhat greater and changeable, as in this part ofthe intestine the presence of gas is often detected.

In regard to the microscopical structure the mid-gut isdivided into two regions. The anterior region is characterizedby the presence of epithelial cells of distinctly glandularcharacter, and resembling the liver-cells. In it, as in the liver,we encounter two kinds of cells; on account of which thisregion of the intestine may be called the heteromorphousregion (PI. 23, fig. 23, im). Without any visible boundary theheteromorphous region passes into the homomorphous regionof the intestine, the cylindrical epithelium of Avhich is formedby uniform cells not bearing a clearly glandular character(PI. 23, fig. 25, ep). This transition takes place approximatelyat the point at which the last pair of hepatic ducts open intothe intestine.

The epithelial layer of the mid-gut, which is scalloped orexpanded, when filled up with faecal masses, rests on amembrana propria, clothed exteriorly with a muscular mem-brane of circular and longitudinal striated fibres (PL 23,fig. 25, mm).

Into the posterior portion of the pars tecta intestini openthe Malpighian vessels (Text-fig. 6, vipp, mpa) at a pointdefined in certain species of scorpions by the presence of acircular constriction (e.g. in B u t h u s a u s t r a l i s ) .

To the appendages of the mid-gut are referred the stomachgland, liver, and so-called Malpighian vessels which represent

232 E. N. PAVLOVSKY AND E. J. ZABIN

excretory organs, and therefore will not be referred to any-more.

(d) The stomach gland of the cephalothoracic part of themid-gut has received various names from different authors.T. Miiller (9, 1828), Newport (10, 1873) called it the salivarygland, Dufour (11, 1856) regarded it as the cephalothoracicoutgrowth of the liver, whilst the coxal glands he took to besalivary glands. E. Blanchard (12, 1851-9) asserted thatthe scorpions were devoid of salivary glands ; the organsregarded as such by his predecessors being stomach glands.Blanchard (12), however, made a mistake himself by referringto the latter the coxal glands as well.

The stomach gland represents a parenchymatous body ofpentagonal form in general (Text-figs. 3, 5, gvt), lying in thecephalothorax and covering the stomach, nerve-nodes, andcoxal glands from above. In the character of tissue, consistence,and colour this gland resembles the liver very much. In thestomach gland an anterior unpaired process and two lateralones can be distinguished. The degree of their developmentand form varies in the different species of scorpions. Withits posterior surface the gland is immediately adjacent to thediaphragm (Text-fig. 6, d). As the old authors have alreadydemonstrated (e.g. Blanchard, 12), this organ is composed ofnumerous vesicles. They are formed of tall glandular epithe-lium resembling the large liver-cells (PI. 23, fig. 22, zr). Theirprotoplasm is overladen with different kinds of secretion andpigment granules. The nucleus is lost amongst all this massof inclusions. In general it lies nearer to the base of the cellswhich protrude in the form of scallops into the gland cavity,sometimes karyokinesis of these epithelial cells being observedin the adult S c o r p i o m a u r u s .

From the liver-cells these structures differ in their narrowerform. Similarly to the liver, the stomach gland possessesa second kind of glandular cells of smaller size, correspondingto the ferment elements, with a greater amount of ergasto-plasm granules (PL 23, fig. 22, zj). The epithelium (PL 22,fig. 14, gvt) rests on the membrana basilaris clothed exteriorly,

DIGESTIVE ORGANS OF SCOEPIONS 233

as in the liver, with a peritoneal covering, filling up the slitsbetween the lobules of the stomach gland. It consists oflamellous connective tissue forming a reticular mass insection with cells in its nodes.

The correct nomenclature of an organ is closely connectedwith the elucidation of its physiological significance. Asregards the stomach gland of the scorpion, it has not beenelucidated previously to our work, as only Blanchard (12) hadmade tests on the digestion of insects in v i t r o by the actionof this organ. A more detailed investigation of the fermentshas not hitherto been conducted. The question as to whetherthis gland represents a ' cephalothoracic liver ' or some otherorgan, has already been discussed by one of us on purelymorphological data, the following views having been expressed(Pavlovsky, 1, 1917, pp. 71, 72).

In favour of the view, according to which the stomach glandis regarded as a liver, is their external likeness, a similarconsistence, the presence of two kinds of cell-elements (as inthe liver), the presence of a peritoneal covering and, of course,the relation to the mid-gut of the scorpion. Against sucha supposition are its independent position in the cephalothoraxand certain data of development. On dissecting fairly welldeveloped embryos of H e t e r o m e t r u s c y a n e u s (with fullyformed body and appendages) the sharp difference betweenthe form of the stomach gland and that of the liver was mani-fested. The former was a tubular structure, in which theanterior extremity and two lateral outgrowths opening oneither side into the dilatation of the mid-gut—representing thestomach—have become distinctly expressed.

At the same period the liver was represented by rudimentsof quite different aspect—in the form of dense clusters on thesurface of the pre-abdominal portion of the mid-gut. Duringthe further development, when the tubules of the cephalo-thoracic gland thicken and produce secondary diverticula, italready assumes a likeness to the liver, this likeness presentingalready a secondary character, at any rate in Scorpionidae.These considerations point to the cephalothoracic gland being


a structure distinct from the liver, which is also corroboratedby the data of the present work, which will be described in thesecond part.

(e) The liver (Text-fig. 5, hpr). Into the pre-abdominalportion of the mid-gut on either side of the body open fourducts (Text-fig. 6, dh) of a large digestive gland filling up theentire cavity of the pre-abdomen in the scorpion. This organhas been known for a long time. Meckel (13, 1809), Dufour(11, 1855), Blanchard (12, 1854), Guieysse (14, 1908-9) calledit the liver, Treviranus (15, 1912) the fat-body, and Newport(10, 1843) blind glandular appendages of the mid-gut.

Its form, when viewed in the animal with the tergitesremoved, is due to the interior shape of the body-cavity.Along the median body-line it has a dorsal depression, in whichthe heart with the pericardial sac lies. On either side of itthere are six openings for the passage of the dorso-ventralmuscles. The tipper surface differs in the members of thedifferent families of scorpions. Thus the fam. Buthidae ischaracterized by a continuous liver (Text-fig. 5, ltipr), the lobulesbeing present only on its lateral and anterior surfaces. Theliver of Scorpionidae is lobular not only on the inferior but onthe superior surface as well, which is many times intersected intransverse direction, the slits between the lateral lobules notreaching the edges of the longitudinal heart groove. A lessregular lobularity of the liver than in Scorpionidae is observedin Chactidae and Vejovidae.

The microscopical structure was already investigated byGuieysse (14), who discovered that the digestive apparatus ofB u t h u s o c c i t a n u s is constructed after the type of Crus-tacea Decapoda. In the liver he describes infrequent ' dark 'cells, the protoplasm of which stains not only with acid,but with basic stains as well, and a second kind of cellswith different inclusions. The larger cells of the latterkind are distinguished by transparent protoplasm of fibrillarstructure and spherical concretions, whilst the remaining cellsare highly vacuolized and also contain spherical inclusions.The concretions are of two kinds. One is represented by homo-


geneous globules staining deeply with safranin ; in polarizedlight they are inactive ; they are never encountered in thecavity of the blind outgrowths of the liver. These inclusionsrepresent food particles accumulated in the cells. The otherconcretions consist of smaller granules, varying in aspect andstructure. They are distinguished by crystalline form, do notstain with safranin, exhibit double refraction of light, but notthe phenomenon of a cross ; these are also frequently encoun-tered in the lumina of the liver lobules and, probably, representexcretory products.

According to our own observations the liver of the scorpion(adult B u t h u s eupeus) consists of two kinds of cells.Some are larger (PI. 23, fig. 23, zr), their nuclei (n) are situatedin the middle of the cell, or nearer to the base ; the protoplasmis filled up with large globular inclusions of different size. Theinclusions are homogeneous and their substance acidophile.It stains with Giemsa's solution and with ' panchrom ' ina pink colour, sometimes with different tints of violet. Thefree surface of the cell is outlined quite definitely. Besidesthe inclusions named, the protoplasm also contains pigmentgranules (xp) disposed in groups. In unstained balsam pre-parations they are of brown colour, and in those stained withGiemsa's stain black-green.

These are, probably, excretory granules (Hamburger (16)regards them, according to Fausek's (17) data, as guaninformations), as they are also encountered in the cavity of theliver lobules. The large cells described absorb the food particlesand correspond to the following elements in the other Arach-nids : cellules caliciformes—Bpeira (Schimkewitsch, 1884),large liver-cells in Argyroneta (Hamburger, 16, 1910, Text-fig. 12, grz), the digestive cells of the liver in Thelyphonus(Tarnani, 18, 1904), the liver-cells in Thelyphonus (Schimke-witsch, 19,1906), the large-lobed (glandular) cells of the pseudo-scorpion (Stchelkanovtsev, 20, 1903), and the analogous cellsof the Phalangidae (Birula, 21, 1891).

The cells of the second kind are few compared with theabsorbing ones. They are compressed by the latter and are

236 E. N. PAVLOVSKY AND B. J. ZARIN

distinguished from them by well-marked characters. Thefundamental protoplasm of these cells contains numerousbasophile inclusions in the form of granules, filaments, &c.Lying close to each other they form strands staining deeplywith Giemsa's stain in a blue-violet colour. These strandsform layers between the acidophile globular inclusions of granularstructure (xs). The nucleus is situated in the band of basophilesubstance and also stains a dark-blue colour.

This type of cells corresponds to the ferment cells of theliver in Crustacea and the Arachnoidea mentioned.

Both kinds of cells form in the liver lobules a- continuouslayer resting on the membrana propria, outside which, con-trary to other Arachnids, there are no muscle elements at all.

Instead of these the liver of the scorpion is clothed by awell-developed membrane, analogous to the similar structurein the rest of Arachnoidea. This membrane consists, as in thestomach gland, of lamellous connective tissue (PI. 23, figs. 23,24, up, upn), in the dense nodes of which the connective-tissuecells with an oval nucleus and fine granular protoplasm arearranged.

The membrane stains blue after Mallory. It unites directlywith the membrana propria of the liver lobules, which it bindstogether. The superficial layer of the membrane is smooth ;into it penetrate outside narrow lacunae conducting the cavityfluid, which cannot circulate freely in the mass of the coveringtissue on account of its spongy structure. Besides the blood-lacunae there ramify in it also the so-called Malpighian vessels,which nowhere pass beyond the limits of the liver membranedescribed.

In the cells of the covering membrane of the liver arefrequently encountered globular inclusions similar to those ofthe absorptive cells. Guieysse (14) says nothing in his workabout this membrane of the scorpion. Detailed observationson the liver of spiders are given by Oetcke (22, 1912), whodescribes in the covering of the liver only polygonal connective-tissue cells ; in them are encountered all the kinds of inclusionsfound in the epithelial elements of the liver, on account of


which the author named considers that the membrane takespart in the metabolism, the accumulation of reserve nutritivesubstances and excretion.

It is hardly to be doubted that in other Arachnids thisliver membrane, identified by Bertkau (23, 1884) with thefat-body of insects, also plays an analogous r61e.

Although the globular inclusions in the liver membrane ofthe scorpion stain a dark colour with osmic acid, the unsuitableterm ' fat-body ' should not be retained for it, in order to avoidany suggestion of even remote similarity to the fat-body ofinsects.

The efferent ducts of the liver have the same structure asthe liver lobules ; their cells enter the intestine, where, accord-ing to the site, they either spread on all its circumference or aregradually replaced by tall cylindrical epithelium with a weakglandular function.

D. H i n d - g u t .

A true proctodaeum is represented in the scorpions by thehind-gut, or rectum occupying only part of the ultimate seg-ment of the post-abdomen (Text-fig. 5, if ; PL 23, fig. 17, ip).Its tall epithelium is covered with chitinous cuticle passing atthe edge of the anal aperture into the chitin of the soft articula-tion membrane between the poison sac and the adjacent body-segment. The gaping anal aperture (situated on the ventralside of the body) is surrounded by four hemispherical pro-tuberances—the diverticula of the wall of the intestine (Text-fig. 7, ip, pa; PI. 22, fig. 16, pa). It lies in the middle of arosette formed by these protuberances. When the hinder portionof the intestine is drawn inside, the anal aperture becomesclosed by special platelets of hard chitin (Text-fig. 4 ; PI. 23,fig. 19, ha), which are of a complex structure in H a d r u r u sh i r s u t u s . There are four of them here ; inside they are joinedby special adaptations of the block type which serve to turnall the platelets outwards simultaneously.

Near the anal aperture the hind-gut is suspended on anoblique muscle running antero-posteriorly and supero-inferiorly

NO. 278 R

238 E. N. PAVLOVSKY AND E. J. ZARIN

from the middle of tergite V of the post-abdominal segment.The ends of the muscle clothe the superior and lateral surfacesof the intestine, being attached to those parts of it which formpapillae when evaginated. On contracting the muscle describeddraws the hind-gut upwards and compresses its sides, on accountof which it can be named m. l e v a t o r an i (Text-fig. 7 ;PI. 22, fig. 16; PI. 23, fig. 18, ml48).

It should be noted that hitherto the intestine of the scorpionhas been represented in the literature by an old and erroneousdrawing belonging to Newport (1845) (E. Lankester, 24, 25 ;Lang, 26 ; Daiber, 27) in which the hind-gut is shown to bedisproportionately long (it begins from the point at which theMalpighian vessels open into the intestine). However, in allembryological works the data conform with each other andprove that the proctodaeum of the scorpion is invaginated onlyto half the length of the ultimate post-abdominal segment.The union of the lumina of the mid- and hind-guts, and,consequently, the establishment of a continuous intestinal canal,takes place only after the first moult of the new-born scorpion.

2. THE DIGESTIVE FERMENTS OF THE SCORPION.

The ferments of scorpions were also dealt with by someprevious authors. Blanchard (12) prepared the stomach glandand tested its proteolytic properties—by an imperfect method,it is true—by action on a fly. He applied the correct zootomicalmethods and prepared the glands studied from a scorpion justkilled ; however, the physiological-chemical part of the investi-gation was imperfect, as the estimation of the enzymes wasnot conducted beyond the proteolytic ferment, and this wasdone roughly. A separate note was devoted by Blanchard (28)to the function of the liver in the Arachnids, including thescorpions. Contrarily to Kruckenberg (31), Fischer (29) andKobert (30) did not apply the correct zootomical methods intheir investigations, as they employed dry animals or alcoholspecimens for the extraction of ferment. The digestive organswere not prepared separately, but the body of the scorpionscut into pieces was infused in a physiological solution of


common salt with the addition of toluol or sodium fluorideat 38° C. during a minimum of 24 hours ; extracts preparedat a lower temperature contained an extremely small amount offerment. We believe that the application of the physiologicalsolution for the preparation of extracts of organs of live animalsis not expedient, since this solution helps to maintain thevitality of the cells during a certain period of time. In orderto render the extraction of the ferments successful the cellsshould be destroyed, which is more readily effected by grindingthe organs in water or in glycerine. It is probably due to thelatter circumstance that, contrary to the data obtained hjFischer (29) and Robert (30), in our extracts prepared at roomtemperature the ferments were readily detected.

The results of the investigation of material prepared in sucha manner by Fischer and Robert can hardly be deemed satis-factory for the solution of the questions propounded by them.

Methods of I n v e s t i g a t i o n .

The material was prepared as follows. The chloroformedscorpions were dissected in a glass bath with a wax bottom ina physiological solution of common salt (0-75 per cent.). Thestomach gland was first removed and put into a small porcelaincup, at the bottom of which there was some well-roasted sea-sand and several drops of glycerine. Then the entire mid-gutwas removed together with the liver ; the latter was separatedfrom the genital glands lying between its lobules and finallyseparated from the mid-gut. Pieces of the liver were placedin the second porcelain cup. After that the intestine wasdivided into two halves corresponding to pars tecta and parsnuda, and these parts were placed into the third and fourthcups. When all the scorpions were prepared and their organs-distributed in cups, each portion was ground with a glass pestletill a uniform mass was produced. Then to the cup wereadded about five drops of glycerine, its contents quickly stirredand at once poured into a glass jar with glycerine, labelledaccordingly. As an antiseptic to the glycerine were addedseveral drops of toluol following Fischer's example (30 a).

R2

240 B. N. PAVLOVSKY AND E. J. ZARIN

The jars were closed with ground corks, repeatedly shaken andleft to stand at the temperature of the room. Glycerine itselfprevents the multiplication of microbes, and this effect isaugmented by toluol, with the result that the glycerine extractsof the digestive organs remained without deterioration forseveral months, as our experiments have shown. Unfor-tunately, we had but very few scorpions at our disposal. Inall, the analyses-of ferments were made in three portions ofextracts which were prepared in the following proportions.

F i r s t Expe r imen t .—Four specimens of B u t h u sdissected (received by post from Teheran from N. K. Bokilion).Their stomach glands and liver were ground each in200 c.c. of glycerine, to which were added 8 drops oftoluol. The portions of the mid-gut were ground each with17-0 of glycerine and the same amount of toluol. The materialwas prepared on April 12, 1917.

Second Expe r imen t .—The stomach glands and liversof two B u t h u s (Teheran, N. K. Bokilion) each with 20-0 c.c.glycerine and 8 drops of toluol, July 24, 1917.

T h i r d exper iment .—The stomach gland and liver ofone B u t h u s e u p e u s (from Julek, Perovsky district, Sir-DariaReg. by P. I. Ivanov) each ground with 10 c.c. of glycerine,8 drops of toluol added to each. Extract October 31, 1917.

On account of the extremely limited amount of materialinvestigated, and owing to the absence in sale of certain specialreagents at that time, we were compelled to limit our task toa qualitative estimation only of the following ferments :(1) catalase, (2) diastase, (3) inulase, (4) invertase, (5) lipase,(6) pepsin, (7) trypsin, and (8) chymosin.

C a t a l a s e .

The catalytic properties of some animal and plant tissueswere already established by Schonbein (43) in 1863. Moredetailed investigations on catalase were published by Loew (44)only in 1901. As is known, the catalase is capable of decom-posing hydrogen peroxide into molecular oxygen and water :2 H2O2 = O2 + 2 H2O. This ferment is widely spread inanimal and plant tissues. The catalase of scorpions was

DIGESTIVE ORGANS OP SCORPIONS 241

studied also by Kobert. This author worked on Asiaticscorpions which were preserved more than five years in 70 percent, alcohol, and obtained negative results.

It is true the method applied by Kobert for the detection ofthis ferment was very primitive : he added the extract ofscorpions prepared with the physiological solution of commonsalt to a 30 per cent, solution of hydrogen peroxide and observedthe escape of the bubbles of gas.

For the estimation of catalase we used a special apparatusconstructed by one of us (Zarin, 45). This apparatus con-sists of an ordinary 30-gramme phial, an S-shaped glasstube, and test-tube, the latter graduated to show the volumein the tenth parts of c.c.

P rocess of Analysis .—2 c.c. of extract of fermentsare mixed with 8 c.c. of water, the mixture filtered into theabove-named phial to which are added 10 c.c. of 1 per cent,solution of hydrogen peroxide. Then the phial is stopped witha rubber cork through which the S-shaped tube passes ; thecontents of the phial are mixed, and it is placed in a vesselcontaining water (glass, bath, &c), the level of which shouldbe about 2 cm. below the lower end of the S-shaped tube.The graduated test-tube is then filled with water and attachedto the end of the S-shaped tube in such a manner that no airbubbles can penetrate into the test-tube ; into the latter iscollected the oxygen evolved, the volume of which was estimatedin our experiment after 24 hours.

The results obtained were as follows: The glycerine extractof the liver of scorpions tested evolved from the hydrogenperoxide 0-3 c.c. of oxygen in the first experiment, but in thesucceeding two experiments no oxygen was evolved. Neitherwas any oxygen evolved from extracts of the stomach glandand mid-gut.

A m y l a s e .

Amylase is capable of converting starch and glycogen tomaltose. The presence of an insignificant amount of amylasein the organism of the scorpion was established by Kruckenberg,Fischer, and Kobert.


The method of estimation of amylase applied by us wasas follows : To 2 c.c. of glycerine extracts of the above-namedorgans in the test-tube were added 8 c.c. of water and per 0-1,0-3, and 0-5 c.c. of 0-5 per cent, solution of dissolved starch(amyl. solubile), and after shaking the contents the test-tube•was immersed in a water bath at a temperature of 45° C.Then the test-tube was taken out of the water bath and, oncooling, to its contents was added an aqueous solution ofiodine in potassium iodide by drops.

As is known, on being heated in the presence of amylase thestarch has time to be converted into dextrins and maltose, onaccount of which the liquid assumes a slightly darker colour afteraddition of iodine, whereas in the absence of amylase the starchremains without alteration and the liquid stains a deep dark-blue colour.

In all our three experiments conducted by the methoddescribed the presence of amylase was established only in theextracts produced from the l ive r of the scorpions ; and onacting with 2 c.c. of extract on 0-5 c.c. of the starch solutionduring one hour, the iodine produced a negative reaction tostarch. In all the remaining extracts of the stomach glandand mid-gut negative results were obtained : on acting with2 c.c. of extract on 0-1 c.c. of starch during 2 hours iodineshowed a positive reaction to starch.

I n u l a s e .

Besides starch and glycogen in plants there is a carbohydratein the form of reserve material—inulin—especially in thefamily Compositae.

Under the influence of a special ferment—inulase—inulin isconverted into fructose.

Kobert discovered inulase in scorpions as well. According tothe data of this author the solution of inulin, to which wasadded the extract of scorpions preserved in alcohol, reducedPehling's liquid after 48 hours standing.

For the estimation of inulase we added to 10 c.c. of 1 percent, solution of inulin 3 c.c. of the extracts tested and, as


a preserving agent, 5 drops of toluol. However, after standingthree days at 37° C. this solution failed to reduce Fehling'sliquid. Thus, the results obtained do not confirm Robert'sdata.

I n v e r t a s e .

As is known, under the influence of invertase the moleculeof cane-sugar (saccharose) takes up water and is split into twoparts producing grape and fruit sugar.

Invertase belongs to the number of ferments very widelyspread in the animal and vegetable kingdoms. Concerning itspresence in the organism of scorpions there exist no data inthe literature.

For the estimation of invertase Ave add to 100 c.c. of 5 percent, solution of saccharose 5 c.c. of extracts of the organs ofscorpion named and 1 e.c. toluol, and allow the mixture tostand for 48 hours at 88° C. At the end of this period the rota-tion of the plane of polarization of these solutions was estimatedwith the result that no difference was observed in this respectbetween the experimental solutions and the control solution ofsugar in glycerine. Thus, it is possible to conclude that themid-gut and its glands in scorpions does not contain anyinvertase.

L i p a s e.

The methods of estimating the fat-splitting ferments orlipases are based on the capability of the latter of splitting fatsinto free fatty acids and glycerine, according to the formula :C3H3(O.CnH2n.1O)3 + 8H2O = CgH^OH^ + SCnH^Oij.

In the literature there are no data regarding the fat-splittingferments in scorpions.

For the estimation of lipase we employed a 10 per cent,emulsion of olive oil.

To 5 c.c. of this emulsion poured into a spacious test-tubewere added 2 c.c. of the extracts tested and, as a preservingliquid, 3 drops of toluol.

The test-tube was placed for 1 day into the thermostat at37° C, and afterwards for 2 hours in a water bath at 55° 0.

244 B. N. PAVLOVSKT AND E. J. ZAHIN

At the expiration of this period and on cooling, to the con-tents of the test-tubes were added 10 c.c. of a mixture of equalvolumes of alcohol and ether after preliminary neutralizationand the liquid was titrated with one-tenth of normal solutionof caustic sodium in the presence of phenolphthalein asindicator.

The results obtained were as follows :The extract of liver evoked an increase of acidity in the

emulsion, as compared with the control test-tube—

in the I experiment to 0-15 c.c. of one-tenth normal NaOH.» II „ 0-55„ i n „ o-2o

In the extract of the stomach gland an increase of acidity inthe emulsion to 0-1 c.c. of one-tenth normal NaOH was observedonly in the second experiment, whilst in the first and secondexperiments its acidity remained unaltered.

The extracts from the mid-gut did not. evoke any visibleincrease of acidity.

P r o t e o l y t i c F e r m e n t s .

As is known, the splitting of proteins is usually effected bymeans of the peptic or tryptic ferments.

The first group of ferments act in an acid medium and splitthe proteins only to the formation of peptones. The secondgroup of ferments act in a neutral or alkaline medium, theprocess of splitting proceeding right to the formation of amino

' acids.P e p s i n .

In the literature there is only one indication by Blanchard(19) of the presence of a proteolytic ferment acting in an acidmedium in the stomach of the scorpion. For the estimationof pepsin we applied 10 per cent, gelatin acidulated withhydrochloric acid to the degree of a distinct acid reaction ; ineach test-tube with gelatin were added 2-3 drops of theglycerine extracts tested. The experiment was conductedat the temperature of the room.


In the test-tubes containing extracts of the liver and stomachgland the process of liquefaction of the gelatin commencedafter 2 days, the extract of liver liquefying the gelatin muchquicker than the extract of the stomach gland.

In the test-tubes with extracts from the intestine liquefactionof the gelatin did not take place after the expiration of onemonth.

Thus, according to the data given above, the presence ofpepsin in the liver and stomach gland of the scorpion isestablished.

T r y p s i n .The presence of the tryptic ferment in the organism of the

scorpion was mentioned by Kruckenberg and Fischer (29).For the detection of trypsin we employed the two following

methods : (1) neutral 10 per cent, gelatin and also gelatin ofthe same concentration but alkalized with 1 per cent, of soda ;(2) the method introduced by Grass, Fuld, and Michaelis (46),which is as follows : 0-1 gm. of casein is dissolved by heatingin a small amount of water, in the presence of 10 drops of10 per cent, solution of soda, water is added till the solutionamounts to 200 c.c, and the latter is then filtered.

To 5 c.c. of the transparent nitrate in test-tubes were addedin our experiments 2 c.c. of the glycerine extracts of fermentsto be tested, and the test-tubes were immerged for one hourin a water bath at 37°-40° C.

On expiration of the period mentioned the contents of thetest-tubes—if not sufficiently transparent—were filtered, andto them was added carefully by drops 025 per cent, solution ofacetic acid.

In the presence of trypsin the casein is split, being convertedinto combinations which do not precipitate after the additionof acetic acid, whereas the unaltered casein is precipitated byacid.

The extracts of liver of the scorpions tested evoked in all thethree experiments liquefaction of both the neutral and alkalinegelatin, and produced a distinctly positive reaction on trypsinwith the casein test described above.

246 B. N. PAVLOVSKY AND E. J . ZARIN

The extracts of the stomach gland also liquefied, althoughnot so energetically as those from the liver, the neutral and'alkaline gelatin ; the casein test, however, exhibited negativeresults. This is, probably, due to the fact that gelatin presentsa more sensitive reagent to trypsin than casein as the experi-ments of Fermi have shown.

The extracts from the intestine did not liquefy the gelatin,and exhibited negative results with the casein test as well.

C h y m o s i n .

Chymosin or the rennet ferment is capable of coagulatingmilk by converting its casein into a form not yet elucidated.The greater amount of casein is precipitated in the form ofparacasein by the action of the chymosin in the presence ofa sufficient quantity of calcium salts.

There are no data in literature regarding the chymosin inscorpions.

For the estimation of chymosin 10 c.c. of milk are mixed upwith 90 c.c. of water and 10 c.c. of 10 per cent, solution ofcalcium chloride. To 5 c.c. of this mixture in test-tubes areadded per 20 drops of the above-mentioned glycerine extractsand the test-tubes immerged in water at 40° C.

In the test-tubes which contained the extract of the liverof scorpions the casein of the milk coagulated in all the threeexperiments in the course of 10-15 minutes.

In the test-tubes containing extracts of the stomach glandthe casein coagulated after 50 minutes only in the secondexperiment ; in the first and third experiments no coagulationof the milk was produced during 4 hours at 40° C, after whichthe experiment was interrupted.

In the test-tubes containing extracts of the intestine no pre-cipitation of the casein was observed during 4 hours at 40° C.

On comparing the distribution of the ferments according tothe different portions of the digestive organs, we are enabledto answer the question as to whether the stomach glandand liver are analogous to each other, and in this connexionto consider the nomenclature of these organs. The liver


differs definitely from the stomach gland in that it is capableof producing amylase ; besides, it was twice found to con-tain catalase. Thus, the stomach gland is poorer in fermentsthan the liver. On comparing the results of the experi-ments it strikes one that in the stomach gland werediscovered lipase and chymosin in the second experiment,whereas they were absent in the first and third experiments ;the other ferments also being more active than in the lattercase. This nonconformity of the results of the experimentsmay probably be due to the experimental scorpions beingin different stages of digestion and assimilation of the nutritivesubstances.

Such a difference is the more remarkable that in the secondexperiment the extract of stomach glands (the glands of twoscorpions in 20 c.c. of glycerine) was weaker than in the firstexperiment (four glands in 20 c.c. of glycerine). '

On comparing the action of the extracts of glands with theextracts of the mid-gut it is necessary to note the completeabsence of ferments in the latter case. The interior lining of thegreater part of the pre-abdominal portion of the intestine hasthe same structure as the liver lobules, i. e. consists of fermentand absorptive cells. On theoretical grounds the correspondingpart of the intestine is capable of producing ferments, and itis impossible to deny this property on account of its micro-scopical structure. The final solution of this question ispossible only after a new investigation of more concentratedextracts than those at our disposal.

At any rate, it can be asserted that the stomach gland andthe liver are not analogous to one another and thereforedeserve distinct names. In respect to function, they aredistinct from the mid-gut, this physiological difference standingin connexion with the peculiarities in the structure of the glandsand their anatomical distinction. These data combined allowus to regard the digestive glands of the scorpions as specialorgans, but not simple blind diverticula of the mid-gut, as wasmaintained with regard to the liver in Arthropoda (andMollusca) by Bernard (39) and Jordan (48).

248 B. N. PAVLOVSKY AND E. J . ZARIN

3. ON THE WORK OF THE DIGESTIVE GLANDS IN

SCORPIONS.

The food of scorpions is represented exclusively by liveArthropods—insects, myriapods, Araneina, and, according toBirula (32), also earthworms, which scorpions do not refusein captivity. Their behaviour toward moisture varies. Birulastates that the scorpions may be divided into two groups—hydrophiles, living in the humid medium of the tropical orfoliaceous forests ( P a n d i n u s , I s o m e t r u s , E u s c o r -pius) , and xerophiles inhabiting the forestless, desert areasand quicksands ( B u t h u s , L i o b u t h u s , A n o m a l o -b u t h u s , S c o r p i o , and others). The scorpions of the lattergroup may be completely deprived of water for several years.Another advantageous feature of the organization of theseanimals is their capability of starving. Noe (33) observed acase of starvation of a scorpion during 6 months, and Jacquetduring 368 days.

The scorpion grasps its prey with the chelae of the pedi-palps. Being pre-eminently tactile organs the pedipalps alsoserve to hold the prey while it is being killed with the stingand during the succeeding act of sucking. The denticles of theinner margins of the digits of the chela, the arrangement ofwhich is very important in systematics, belong to the group ofchactoids, as they consist only of thickenings of the pigmentedchitin. They prevent the prey from slipping when it is beingheld. It is hardly probable, however, that their role is onlymechanical, as numerous canals perforating the chitin approachthem. The question whether these canals represent theterminal armature of organs of sense could be solved by specialhistological investigation.

' After taking hold of the prey with the chelae ', writesBirula (32) (loc. cit., p. IIS), ' the scorpion starts to devourit directly in case it is not large and does not trouble him verymuch with its movements ; if the prey struggles too much,the scorpion . . . carefully approaches his sting to it . . . andpricks it,' thus poisoning the creature captured. Then he


proceeds to rupture the integuments of the prey with the clawsof the chelicerae, grasps it closely with the open parts of thepre-oral cavity, and begins to suck out its contents. Thewalls of the cavity named are composed, as we have alreadymentioned in the first part of this work, of several partitions.In order to render the sucking of the prey efficient it is necessarythat the air should not penetrate through the slits between theseparate parts of the walls of the pre-oral cavity inside it,where a negative pressure is produced by the action of therostral muscles. The firm closure of the slits of the pre-oralcavity is due to the soft chitinous membrane of the maxillaryappendages, the ' pads ' of the inner surface of the basal jointsof the pedipalpi and a large number of hairs on the partsnamed and on the infero-lateral surfaces of the chelicerae.The chitinous hairs appear to block up the fissures, thus playinga purely mechanical role, on account of which they may betermed ' byochaetae '. The hairs covering the rostrum probablyserve as a filtering apparatus for the liquid food sucked in, aswas supposed by Tarnani (18) with regard to T e l y p h o n u s .The sucking of the prey is effected by combined action of thepharyngeal and post-cerebral sucking apparatus. Theoreticallytheir action can be represented as follows. Whilst the post-cerebral sucking apparatus remains closed the food passes fromthe pre-oral cavity into the pharyngeal apparatus, which pro-duces the sucking action due to the contraction of all itsdilatators (mm. d i l a t a t o r e s p h a r y n g i s , Text-fig. 7 ;PI. 22, figs. 3, 4, 8, m9S, m99, mUO, mUl, ml42, and mU4).When the entire pharyngeal chamber is filled with the liquidtaken up, the latter is pushed farther into the oesophagus bycontraction of the pharyngeal sphincters, which probablydoes not proceed simultaneously. It is to be supposed thatat the beginning the sphincters situated immediately above themouth opening (Text-fig. 7 ; PI. 22, fig. 8, ml30 a) contract, inorder to prevent the food from escaping from the pharynx backthrough the mouth. When the latter closes the remainingsphincters of the pharynx contract (PI. 22, figs. 3, 4, 5, ml30,ml39) and push its contents into the oesophagus and farther

250 E. N. PAVLOVSKY AND B. J. ZARIN

into the post-cerebral sucking apparatus, which at the sametime produces a sucking action by contraction of its lateraland radial dilatators (Text-fig. 7 ; PI. 22, figs. 12, 13, ml45,ml46, ml46 a). The concluding moment in the progress of thefood to the intestine is due to contraction of the sphincters ofthe post-cerebral sucking apparatus (ml47 ; Text-fig. 7, us),whilst the pharyngeal sucking apparatus continues to remainclosed. In this way the nutritive substance under observationprogresses from the pre-oral cavity into the intestine of thescorpion. In the process of nutrition a certain role, of course,belongs to the rostrum as well, but it is difficult to ascertainin what manner its action is combined with the work of thesucking apparatus.

In cases when the scorpion devours an arthropod with softinteguments, it kneads its prey and presses out its contents.But its food is not always composed of flies and spiders.It is also capable of devouring its own kin and also thecarabids—Procrustes banoni—clothed with hard chitin.In such cases the sucking is effected chiefly by the actionof the sucking apparatus alone, as the pressing out of thecontents of the prey is hardly possible to a great extentowing to the hardness of the integuments. In suckingthe food not only the liquid constituents are consumed,but the hard ones as well, e. g. muscles, epithelial tissue, &c.The latter must be liquefied in order to pass into theintestine of the scorpion. From where are the fermentsobtained for the preliminary peptonization of the food proteins ?An analogous question was raised by Bertkau (23), who assertedthat no such ferments were present in the cephalothorax ofthe spider, and that they were produced only by the liver(Chylus Magen). But a year later (1885, 4) he arrived at adifferent conclusion on establishing the liquefying propertyof the extract of the maxillae in spiders which contain thesalivary glands. This property he refers to the action of theproteolytic ferments of the latter organs. The poison glandsof the chelicerae in spiders are inactive in this respect, accordingto Bertkau.


Owing to lack of material we were unable to investigate thephysiological properties of the maxillary glands in the scorpions,on account of which we shall meanwhile restrict ourselves totheoretical considerations. The oral armature of the scorpionis served by the maxillary glands alone, as there exist noanalogous organs either in the rostrum, the chelicerae, or thecoxal joints of the pedipalpi. No other source for theproduction of the proteolytic ferment could be found onanatomical examination. It might be suspected that the poisonglands of the scorpion contain these elements in the secretionintroduced into the body-cavity of the prey by the sting. Itis possible that the secretion produces a peptolysing effect onthe proteins, apart from its specific toxic action. At present,before we have carried out any experiments in this direction,we must answer this question in the negative, owing to thedata of Birula exposed above, according to which the scorpiondevours its prey without poisoning it, if it is small and affordsno resistance. In this case liquefaction takes place without theparticipation of the secretion of the poison glands.

The food sucked in passes at first into the stomach and thestomach gland, where it is acted upon by pepsin, trypsin,chymosin, and lipase. We are unable to state how long itremains here, and by what stages it passes through the parstecta intestini into the liver. In the latter the food is actedupon also by catalase and amylase, besides the fermentsenumerated. As is known, the amylolytic ferment acts uponstarch and glycogen. Starch cannot pass as such into the mid-gut of the scorpion without being previously converted intoa soluble condition. Evidently the amylase is present in theliver of the scorpion for the treatment of glycogen.

The mid-gut of scorpions is of insignificant volume comparedwith the cavities of the liver lobules. Not only the ileum, butthe greater part of pars tecta s. hepatica intestini as well,contain formed faecal masses of snow-white colour. Thiscircumstance in connexion with the uniform microscopicalstructure of the epithelium of the ileum and the negativeresults of the investigations on the presence of ferments allow,


if not to exclude the intestine altogether from the number oforgans actively participating in the digestive processes, atleast to diminish its importance in this function. The greatestrole in this respect belongs to the liver, the functions of whichare diverse. Its secretory role is very important as the liverproduces the ferments which serve for the treatment of thethree chief nutritive elements—proteins, fats, and carbo-hydrates. To use a rough analogy, we may say that the liverof scorpions performs the work Avhich in the mammals falls tothe pancreatic gland1 (34, 35) and the intestine, since absorp-tion of the nutritive substances is also performed by the liver inthe Arachnids. The majority of investigators agree in describingthe composition of the liver in the different Arachnoidea asof two kinds of cells—fermentative and absorptive. The latterfunction of the liver-cells Bertkau (23) tried to establish onexperimental data. He allowed spiders to drink water withcarmine and observed that granules of the latter were to befound inside the liver-cells, after the blind diverticula had beenfilled with the stained liquid.

The absorptive cells of the liver are, evidently, representedby the large cells with acidophile homogeneous globular inclu-sions, and without basophile granules in their protoplasm.Whereas it is difficult to prove the direct introduction of foodsubstances into these cells in ordinary conditions in prepara-tions, on studying the mature embryos and new-born pulli ofscorpions with yolkless eggs (fam. Scorpionidae) it is clear,as in the Telyphonus larvae (Schimkewitsch, 19), that yolk-elements penetrating into the body of the embryo from outside 2

are present only in the absorptive, but not in the ferment cellsof the liver.

Fiihrt (36, 1903) states that the absorptive processes in theArthropoda were studied by Bassi (37, 1851), who also fedscorpions with flies into which a stain was injected. Thisreference is founded on some misunderstanding, since Bassi's

1 With regard to the production of ferments the liver of Arachnoideawas compared with the pancreas of the vertebrates.

2 Maybe even in a pre-existing form.


article, as well as that of Blanchard (28), does not contain aword about scorpions.

Bernard (38, 1893), investigating the microscopical structureof the digestive organs in the Arachnids, arrived at the con-clusion that in scorpions, as in spiders, the digestive processesare extended to the covering of the intestinal canal as well.This question is more fully elucidated by Oetcke (22), whoregards the covering membrane of the liver in spiders as theplace of deposition of reserve nutritive matter transferred herethrough the medium of its Nahrzellen (= absorptive cells) inthe form of globular inclusions. During starvation these reservesubstances are returned to the Nahrzellen and disappearaltogether in the animal that had starved for a long time.

In the scorpions, which are capable of starving for a longtime (Jaquet), there indubitably takes place an accumula-tion of reserve nutritive materials in the organism, the outwardevidence of which is presented by the presence in the cells ofthe membrane of the liver of inclusions similar to those in itsabsorptive elements. We were unable to make investigationson glycogen in scorpions, and can only mention that E. Blan-chard (12) and Leconte long ago endeavoured to establish theglycogenic function of the liver. They arrived at the conclusionthat ' dans le moment ou s'opere la digestion, le foie, chezle scorpion, produit de la matiere sucree : cette productioncesse lorsque ranimal est a jeun ' (p. 69).

It remains to consider the significance of the liver as anexcretory organ. Its excretory role is corroborated not onlyby the presence of pigment granules (guanine) in its cells, butalso by certain experimental data. E. Blanchard (12) wrote :' ainsi la matiere colorante [indigo or marengo] qui de l'intestinpasse dans le sang est positivement eliminee par le foie. . . .Le foie sert done bien reellement a epurer le sang ' (loc. cit.,p. 70).

Fairly demonstrative are the experiments on the injectionof ammonia-carmine into scorpions, carried out by one of usand already published (Pavlovsky, 1). Ammonia-carmine wasintroduced into the body-cavity of both adult scorpions and

NO. 278 S


their pulli (Scorpio m a i u u s , B u t h u s a u s t r a 1 is ,B u t h u s c a u c a s i c u s , and B u t h u s eupeus). In severalcases a distinct excretion of carmine by the liver was observed,the liver staining pink which was visible macroscopically.On examination of sections it was observed that the carminewas excreted only by the absorptive cells in which it wasdeposited in the form of minute bright-red granules or pinkglobular inclusions. The ferment cells were always free fromcarmine. The solution of trypan-blue, trypan-red, and isamino-blue produced no effect on the liver.

In the literature there are indications that Cuenot mentionedto Bruntz (40) verbally one case in which carmine was excretedby the liver in the scorpion. Bruntz (41) also observed a similarphenomenon in certain ticks and in Chelifer c a n c r o i d e s ,but mentions nothing as to Avhat liver-cells in the latter formwere capable of excretion.

In regard to secretion the liver of the Arachnids stands close tothe corresponding organ in the Crustacea, in which it also repre-sents an absorptive organ and the storing place for food reserves.

Returning to the fate of the food progressing along theventriculo-intestinal canal of the scorpion, it is necessary todwell on the moment when the excretory products and maybealso the undigested parts of the food accumulate in the luminaof the liver lobules and in the intestine. The formation of thefaecal masses takes place in the pars tecta intestini; in theform of bright-white irregularly cylindrical lumps they fill upalso the ileum of the scorpion and progress along the intestineby contraction of its muscular membrane. The free portionof the mid-gut is easily vulnerable, and it was not infrequentlypossible to observe live scorpions in which, on account ofrupture of the intestinal wall, the faecal masses and air hadpenetrated into the post-abdominal cavity. The latter appearedto be quite dry; notwithstanding such a trauma, which interferedin a large degree with the digestion, the scorpions continuedliving and did not appear sick or weak. The post-abdomencontinued acting, as an organ of defence normally, and only thefunction of ejection of the effete matters was discontinued.

DIGESTIVE ORGANS OF SCOKPIONS 255

The latter takes place as follows in normal conditions. Thefaecal matter is pressed out of the intestine by contraction of itswell-developed muscular membrane, as well as by the action ofvi44 and m60 (PI 22, fig. 16; PI. 23, fig. 18) (according to Beack'sterminology, m44 represents the arthrodio-rectal muscles,and m60 the lateral arthrodio-sternal muscles) ; although thesemuscles are not directly attached to the intestine of thescorpion, they nevertheless produce a certain pressure on it,when on contraction their middle portion thickens. Owingto the increase of the pressure inside the abdomen, the hind-gutand anal papillae are everted outwards, the m. 1 e v a t o r a n i(PI. 22, fig. 16; PI. 23, fig. 18, ml48) tends by contraction todraw the end of the intestine to its former position, this actionbeing counteracted by the pressure inside the abdomen. Suchcorrelation of forces has the effect of pressing the contents ofthe intestine outside. Thus, defaecation in scorpions is effectedwithout the help of any sphincters, which were described togetherwith the dilatators of the hind-gut in I s c h n o c o l u s byL. and W. Schimkewitsch (42).

KEFERENCES.

1. Pavlovsky, E. N.—'Materials on the Comparative Anatomy andDevelopment of the Scorpions '. Petrograd, 1917.

2. " On the question of the structure of the poison glands in theArthropoda", ' Trans. Soc. Natur. St. Petersburg', vol. xlii,fasc. 2, 1912.

2a. "Studies on the Organization and Development of Scorpions",' Quart. Journ. Micr. Soi.', vol. 68, Part IV, 1924.

3. Schimkewitsch, W.—" Etudes sur l'anatomie de 1'Epeire ", ' Ann.Sc. Nat.', ser. 6, vol. 17.

4. Bertkau, Ph.—" Ueber den Verdauungsapparat der Spinnen",' Arch. mikr. Anat.', vol. xxiv, 1885.

5. Gaubert, P.—" Recherches sur les organes des sens et sur les systemestegumentaires, glandulaires et musculaires des appendices desArachnides ", ' Ann. Sc. Nat.', ser. 7, vol. xiii, 1892.

6. MacLeod.—This muscle was also known to MacLeod, " La structurede l'intestin anterieur des Arachnides ", ' Bull. Acad. Belg.', ser.3, vol. viii, 1884. This work was not read in the original.

7. Lankester, Benham, and Beck.—A detailed investigation of themusculature of scorpions, " On the Muscular and Endoskeletal

S2


Systems of Limulus and Scorpio, with some notes on the Anatomyand Generic characters of Scorpions ", ' Trans. Zool. Soc. London ',vol. xi, 1885. The muscles that were not described by Miss Beckare numerated by successive figures beginning from ml38.

8. Huxley, T. H.—Some of the muscles were described by Beck (7) andHuxley, " Pharynx of Scorpions", ' Quart. Journ. Micr. Sci.',vol. viii, O.S., 1860.

9. Miiller, T. — "Beitrage z\ir Anatomie des Scorpions", 'MeckelsArchiv fur Anat. Physiol.', 1828.

10. Newport, G.—" Nervous and circulatory systems in Myriapoda andMacrourous Arachnida ", ' Philos. Trans, of the Royal Society ',1843, Part II.

11. Dufour, L.—" Histoire anatomique et physiologique des Scorpions ",' Mem. pres. par divers savants a l'Acad. des Sciences', vol. 14,1856.

12. Blanchard, E.—' L'organisation du regne animal'. Paris, 1851-9.13. Meckel.—' Beitrage zur vergleichenden Anatomie ', vol. 1, 1809.14. Guieysse.—"Etude des organes digestifs chez le Scorpion", 'Arch.

Anat. microsc.', vol. x, 1908-9.15. Treviranus.—' Ueber den inneren Bau der Arachniden !. Niirnberg,

1912.16. Hamburger, C.—" Zur Anatomie und Entwicklungsgeschichte der

ArgyToneta aquatica Cl.'\ ' Zeitschr. f. wiss. Zool.', vol. 96, 1910.17. Fausek, W. —• " Accumulation of guanin in spiders (Araneina) ",

' Mem. Acad. Sciences', 8th ser., Phys.-Math. Section, vol. 24, no. 3,1909. St. Petersbourg.

18. Tarnani, T.—"The anatomy of .Telyphonus (T. caudatus L.)" .Supplement to vol. xvi of the ' Ann. Novo-Alexandria Instit. ofAgricult. and Forestry '. Warsaw, 1904.

19. Schimkewitsch, W.—" tjber die Entwicklung von Telyphonus cau-datus (L.), verglichen mit derjenigen einiger anderer Arachniden",' Zeitschr. wiss. Zool.', vol. 81, 1906.

20. Stchelkanovtsev, J.—' Materials on the anatomy of the Pseudo-scorpions '. Moscow, 1903.

21. Birula, A.—" Einiges iiber den Mitteldarm der Galeodiden ", ' Biol.Centralbl.', vol. xi, 1891.

22. Oetcke, E.—" Histologische Beitrage zur Kenntniss der Verdauungs-vorgange bei den Araneiden", 'Zool. Jahrb.', Abth. Allg. Zool.,vol. 31, 1912.

23. Bertkau.—" Ueber den Bau und die Funktion der sog. Leber beiden Spinnen.", ' Arch. micr. Anat.', vol. 23, 1881.

24. Lankester, E. R.—"Limulus an Arachnid", 'Quart. Journ. Micr.Sci.', N.S., vol. 21, 1881.

25. " The Structure and Classification of the Arachnida ", ibid., vol.48, N.S., 1905.


26. Lang.—' Lehrbucli der vergleichenden Anatomie '. Jena, 1888.27. Daiber.—" Araohnoidea ", in ' Handb. Morph. wirbellos. Tiere &c.',

Bd. 4, 1913.28. Blanohard, E., in ' C.R. Acad. Sc.', vol. 41, 1855.29. Fischer.—' Ueber Enzyme wirbelloser Tiere '. Rostock, Diss., 1903.30. Kobert in ' Arch, gesam. Physiol.', vol. 39, 1913.31. Krukenberg.—' Vergleichende physiol. Studien'. Experim. Unter-

such. Heidelberg, 1881, V. Abh.32. Birula.—' Faune de la Russie. Arachnides'. Vol. I, Scorpions,

livraison 1, 1917.33. Noe.—' C.R. Soc. Biol.', 1893.34. Plateau.—" Recherches sur la structure de l'appareil digestif et sur

les phenomenes de la digestion chez les Araneides dipneumones",' Bull, de l'Acad. Roy. Belg.', ser. 2, vol. 44, 1887.

35. Griffiths and Johnston.—' Physiology of Invertebrata ', 1892.36. Fiihrt.—'Vergleichende chemische Physiologie der niederen Tiere'.

Jena, 1903.37. Bassi.—' Ann. Sc. Nat.', ser. 5, vol. 15,1851.38. Bernard.—" Notes on some of the digestive processes in Arach-

nids ", ' Journ. Roy. Micr. Soc.', 1893, p. 427.39. Bernard in ' Journ. Roy. Micr. Soc.', 1893.40. Bruntz.—" Contribution a l'6tude de 1'excretion chez les Arthro-

• podes ", ' Arch, de Biologie ', vol. 20, 1904.41. " fitudes sur les organes lymphoi'dea, phagocytaires et excr6-

teurs des crustaces superieurs ", ' Arch. Zool. exper. et gener.',ser. 4, vol. 7, 1907.

42. Schimkewitsch, L. and W. — " Ein Beitrag zur Entwicklungs-geschichte der Tetrapneumones, I-III ", ' Bull. Acad. Sci. Russie ',1911.

43. Schonbein.—' Journ. fur prakt. Chemie', 1863, vol. 89, p. 32.44. Loew.—" Catalase, a new enzyme of general occurrence", 'Rep.

U.S. Dept. of Agric.', 1901, no. 68, p. 7.45. Zarin, E. J.—" An Apparatus for the estimation of catalase",

Works of Agric, Bacteriol. Lab. of Min., 'Agi'ic.', 1913, vol. iv,no. 11.

46. Abderhalden.-—' Handbuch der biochemischen Arbeitsmethoden ',1910, vol. 3, p. 19.

47. Fuhrmann.—' Vorlesungen iiber Bakterienenzyme'. Jena, 1907,p. 29.

48. Jordan.—"Die ' Leberfrage ' bei den wirbellosen Tieren", 'Zool.Jahrbuch', Supplementband 15, III. Abt., 1912.


LETTERING OF FIGURES IN TEXT AND PLATES.

ao, dorsal aorta ; amd, middle eyes ; C, chelicerae ; ch, chitin ; cm,commissure part of cephalothoracic nerve ganglia ; cr, heart; era, supra-oesophageal nerve ganglia; cri, sub-oesophageal nerve ganglia; d,diaphragm ; dg, stomach-gland ducts ; dh, hepatic ducts ; dj, opening ofstomach gland into stomach ; dr, unicellular gland ; dv, coeca of cephalo-thoracic portion of gut; ec, chitinous cuticle ; eca, skin cast duringmoult; en, pre-oral entosclerite ; ep, epithelium ; gs, maxillary glands ;gv, poison glands ; gvt, stomach gland ; ha, covering chitinous plates ;kp, hypoderm ; hpr, liver; ia, fore-gut ; im, mid-gut; ip, hind-gut ;Ig, lymph-nodes ; Ip, lung ; Jma,_s, maxillary processes of first and secondpairs of legs ; lt0, leucocytes ; m, muscles ; mm, membrana muscularis ;31, maxillary processes of legs ; me, membrana externa ; mmp, malpighianvessels ; mp, membrana propria ; mGO, muscles of articulation membraneof poison vesicle ; mpa, anterior pair of Malpighian tubes ; mpp, posteriorpair of malpighian tubes ; m.98, m. dilatator pharyngis subrostralis interior ;m99, m. dilatator pharyngis lateralis; ml30, ml30 a, m. sphincterpharyngis ; ml3S, m. transversus rostri obliquus ; ml39, m. transversuarostri ; mldl, m. rostropharyngis interior lateralis ; ml42, m. rostro-phaiyngis interior medialis; ml43, m. rostri inferior lateralis ; ml44,m. dilatator pharyngis suprarostralis superior; m.M5, m. dilatatoroesophagi retrocerebralis lateralis ; ml46, m. dilatator oesophagi retro-cerebralis radialis ; ml46a, m. dilatator oesophagi retrocercbralis superior ;mliS, m. levator ani; n, nucleus ; neph, nephrocyte; o, oa, anus ; 6b,oral aperture; od, free surface of epithelium ; oc, oesophagus ; one, pre-oral entosclerite ; ore, post-cerebral suctorial apparatus; os, ostium ofheart; P, pedipalps ; pa, anal papillae ; ph, pharynx ; pd, pedipalps ;Pn, soft pad of pedipalps ; q, upper surface of suprapharyngeal nerve-mass ; qu, lower surface of suprapharyngeal nerve-mass ; R, r, rostrum ;rm, dorsal muscles ; tg, stigrna; tm, tentarium musculare; up, upn,peritoneal covering of liver ; us, sphincter (ml47) ; vc, ventral nerve-chain ; vli, blood-vessel; vt, stomach; xb, basophile granules in proto-plasm ; xp, pigment inclusions; xs, granular globular inclusions offerment cells ; xz, acidophile inclusions of resorption cells ; z, cephalo-thoracic gut; zf, ferment cells ; zr, resorption cells ; I-VII, pre-abdominalsegments ; 1-5, post-abdominal segments.

EXPLANATION OF PLATES.PLATE 22.

Kg. 1.—Buthus c a u c a s i c u s (Nordm.). Part of transverse sectionof pullus at the base of the maxillary processes of first and second pairsof legs with alveolar glands (gs) in them. Along the upper part of the


lateral edge of the process of the second pair of legs (Zm<z2) there runsa groove. Carnoy, Giemsa. Z. obj. AA, oc. 1.

Fig. 2 .—Heterometrus c y a n e u s (C. L. Koch). Frontal sectionthrough mouth-opening and chitinous parts surrounding it in new-bornpullus. Corr. subl., acetic acid, Giernsa. Z. obj. AA, oc. 2.

Fig. 3.—Centrurus m a r g a r i t a t u s (Gerv.). Pullus after firstmoult. Sagittal section through plane bordering with the middle planeof the body (along line AA, fig. 4 of same plate). Muscles of the rostrumvisible; the transverse dilatators and sphincters of the pharyngealsucking apparatus are cut at the very point of their attachment to thelateral wall of the pharynx. Only the antero-latcral slit of the latter isinvolved in the section (ph). The maxillary processes of the first andsecond pairs of legs are not drawn. Duboscq, Giemsa. Z. obj. AA, oc. 4.

Figs. 4-8.—Buthus eupeus (C. L. Koch). Pullus before firstmoult. From a series of horizontal sections through rostrum and pharyn-geal sucking apparatus. The figures are enumerated according to thesuccession of sections from above downwards. Duboscq, Giemsa.

Fig. 4.—Same. Section through the ends of the pre-oral entosclerite(one), lateral dilatator of pharynx (m99), and upper part of rostrum.Z. obj. AA, oc. 2.

Fig. 5.—Same. Section on the level of attachment of the superiorrostropharyngeal muscles (ml40). Z. obj. AA, oc. 2.

Fig. 6.—Same. Section corresponding to line BB in fig. 3. Z. obj. AA,oc. 2.

Fig. 7.—Same. Section on the level of the anterior point of attachmentof mm. rostropharyngeales inferiores mediales (ml42). Z. obj. AA, oc. 2.

Fig. 8.—Same. Section on the level of attachment of the inferior rostro-pharyngeal muscles to the pharynx (ml41, ml42). Z. obj. AA, oc. 4.

Fig. 9 .—Hete romet rus c y a n e n s (C. L. Koch). Pigmented pullus.Transverse section of intracerebral portion of the oesophagus. Corr. subl.,acet. acid. Haematoxylin. Eosin. Z. obj. DD, oc. 4.

Fig. 10 .—Heterometrus c y a n e u s (C.L.Koch). New-born pullus.Transverse section of intracerebral portion of oesophagus. In its cavityis seen the detached embryonic cuticle (eca, which is cast off at the firstmoult), and underneath it are found leucocytes that have migrated herefrom the body-cavity. Corr. sublim., acet. acid. Giemsa. Z. obj. DDoc. 2.

Fig. 11.—H e t e r o m e t r u s c y a n e u s (C. L. Koch). Pigmented pullus.Part of transverse section of the wall of the oesophagus with a large gland-cell in the epithelium (dr). Corr. subl., acet. acid. Haematoxylin. Eosin.Z. obj. DD, oc. 4.

Figs. 12-15.—Heterometrus c y a n e u s (C. L. Koch). Pigmentedpullus. From a series of transverse sections through the digestive canal.Corr. subl., acet. acid. Haematoxylin. Eosin.

260 E. N. PAVLOVSKY AND B. J. ZAEIN

Fig. 12.—Same. Section of oesophagus at the slit between the supra-and sub-oesophageal masses of the nervous system. To its lateral wallsare attached weak bundles of m. dilatator oesophagi retro-cerebralislateralis (ml45). Z. obj. AA, oc. 4.

Fig. 13.—Same. Same position, but section passing somewhat posteriorlyto the vertical plane of the posterior end of the supra-oesophageal nervousmass. The radial dilatators of the oesophagus {ml46) and the tentoriummusculare (tni) are visible. Z. obj. AA, oc. 4.

Fig. 14.—Same. Transverse section through the opening of the oeso-phagus (ore) into the intestine (z), into which the digestive gland (dg) alsoopens. Z. obj. AA, oc. 2.

Fig. 15.—Same. Transverse section through cephalothoracic portionof the intestine under which rudimentary ventral diverticula (dv) arevisible. Z. obj. AA, oc. 2.

Fig. 16.—Scorpiops m o n t a n u s (Karsch). Longitudinal sectionthrough posterior part of the ultimate segment of the pre-abdomen withthe anal papillae (pa) evaginated outwards. M. levator ani visible (ml48).Preparation in to t o . Obj. W. II, oc. 0.

PLATE 23.

Fig. 17.—Lychas m a r m o r e u s (C. L. Koch). Longitudinal sectionthrough ultimate segment and adjoining portion of the poison sac in new-born pullus (before first moult). The absence of communication betweenthe mid- and hind-gut (ip, im) is visible. Duboscq's fluid. Giemsa.Obj. W. II, oc. 2.

Fig. 18.—Buthus eupeus (C. L. Koch). Frontal section throughultimate segment of the post-abdomen in new-born pullus (before firstmoult) on the level of the hind-gut anteriorly to the anal aperture.M. levator ani (ml48) visible. Carnoy. Giemsa. Obj. W. II, oc. 4.

Fig. 19.—Hadrurus h i r s u t u s (H. C. Wood). Chitinous platescovering anal aperture. Between them a system of blocks which enablethem to close are visible. Schematized.

Fig. 20.—Scorpio maurus.—Transverse section of post-cerebralsucking apparatus. Zenk.-Form. Osmium. Iron, haematox. Z. obj. AA,oc. 2.

Fig. 21.—Same. Transverse section of stomach (vt) at the level wherethe stomach glands (gvt) and the rudimentary tubular diverticula (dv)open into it. Same staining and magnification.

Fig. 22.—Same. Part of the wall of the stomach gland with the resorp-tion (zr) and ferment cells (zf). Zenk.-Form. Giemsa. Z. obj. 1/12 horn,imm., oc. 4.

Fig. 23.—B u t h u s eupeus.—The opening of the hepatic duct into thegut (shown by arrow). Unna's polychrom. methylene blue. Z. obj. DD,oc. 2.


Fig. 24.—Same. Portion of hepatic lobule in section. Resorption cells(zr), ferment cells (zf), and peritoneal covering of liver (upn) visible.Duboscq's fluid with chloroform. Panchrora. Z. obj. 1/12 bom. imni.,oc. 4.

Fig. 25.—Scorpio m a u r u s . Transverse section of boniornorphousportion of mid-gut. Dominici's stain. Z. obj. DD, oc. 1.

Kg. 26.—Tityus sp. Longitudinal section of maxillary processes offirst and second pairs of legs with numerous glands in them (gs). FromProfessor H. Buxton's preparation. Duboscq's fluid. Z. obj. AA, oc. 0.

jtl

Pavlovsky, del.

Quart. Journ. Micr. Sci. Vol. 70, N. S., PI. 22

Quart. Journ. Micr. Sci. Vol. 70, N.S., PI 23

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on the structure and ferments of the digestive organs of ......the digestive apparatus of scorpions...

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