Book reviews 593

present in the Estuary. Distributions of the major groups-rotifers, cladocerans, copepods--are given together with details of the larvae present. Macrofaunal species (mostly crustaceans and coelenterates) present in the water column are also discussed.

Benthic invertebrates are discussed in Chapter 7. Details of infaunal and epifaunal species (worms, bryozoans, molluscs and crustaceans) are given including commercially important species such as the American oyster (Crassostrea virginica) and the blue crab (Cullinecces supidus). Distributions of benthic invertebrates and of oyster beds are given in Folio Maps 5 and 6. Chapter 8 is devoted to an account of the fish species present in the Potomac. Because of their economic importance and their value as indicators of envir- onmental change, considerable detail is given on the distribution and abundance of many of the species of fish present in the estuary. The fish described are grouped as fresh water, estuarine, marine, andromous and semiandromous species. The detailed distribution of the spawning grounds and the migration routes of both andromous and semiandromous fish are given in Folio Maps 7 and 8.

An account of the commercial and sporting fishing in the Estuary is given in Chapter 10 and it includes statistics of commercial tish landings.

Birds and mammals associated with the Estuary are described in Chapter 9. Details of distribution of many of the species of ducks, geese and eagles are given. The mammals described include the muskrat, nutria, beaver and river otter.

The appendices include complete floral and fauna1 lists of species present together with details of the habitats in which they are found. Appendix 10 lists all the relevant environmental monitoring studies and scientific investigations that have been conducted in the Potomac since 1954. Most of the surveys were conducted in the 1960s and early 1970s.

One aspect of the physical background to the estuary that could usefully have been expanded is the account of the geology of the region. Brief mention is made on pages 20 and 27, but as many of the morphological features of the estuary are related to the local geology, the inclusion of a geological map of the Coastal Plain sediments--ideally as part of the folio map set-would greatly increase the value of the Atlas to planners and other users.

Comprehensive multidisciplinary surveys of estuaries are few in number and I know of none as attractively produced as this. I commend it to all with interests in the Potomac and in estuaries in general.

Considering present book prices, it is hard to understand how such a fine atlas can be produced for as little as A20 .OO.

J. B. WILSON

Advances in Marine Biology, Volume 19 Edited by J. H. S. Blaxter, Sir F. S. Russell and Sir C. M. Yonge Academic Press, London, 1982, 382 pp, ,(30.00

Volumes such as this containing major reviews on widely differing topics are very difficult to review. It is usually impossible to find a reviewer who can competently deal with all the topics covered. It is important, nevertheless, to try to make reviews as penetrating and detailed as possible and to draw attention to the strengths and weaknesses of the work in question.

This review discusses only two of the four papers contained in the volume. They are considered by two separate reviewers.

594 Book reviews

‘The biology of the phoronida’ by C. C. Emig is reviewed by J. P. Thorpe. This review, as in general with the series, is produced to a very high standard and is almost free of printing and spelling errors, although a number of Emig’s illustrations are to a notably lower standard. The English is excellent for an article written by a Frenchman but could still have been improved by tighter editing.

As the author of probably the bulk of recent published work on phoronids, Emig was the obvious choice to review phoronid biology. However, I have some reservations con- cerning the need for such a review. There is not a great deal of research of consequence on phoronids and therefore a review of this length is difficult to justify for its information content. It compares unfavourably with, for example, the excellent review in this series by Ryland (1976, Advances in Marine Biology 14,285-443) on Bryoxoa-a group for which there is a much greater volume of recent literature. A good deal of the important literature is old and has already been very adequately reviewed in the book by Hyman (1959, The Invertebrates, vol. 5, McGraw-Hill, New York) and others; also this and the more recent work (much of it written by Emig) is largely covered in various recent papers by Emig. Presumably to make up the length, parts of the content are included, although of doubtful relevance to reviews of this type. For example, the detailed descriptions of all known larvae (pp. 22-31) and the field-guide type descriptions of each adult species (pp. 43-47) are already largely covered in Emig’s Linnean Society synopsis (1979, British and Other Phoronids, Academic Press, London) for which they are considerably more suitable.

The content of the review largely reflects the author’s research interests and the preponderance in the literature of descriptive accounts of anatomy, larval morphology, embryology and taxonomy. Unfortunately some of the most interesting work on phoronids (indeed almost the only experimental work), the excellent nervous system studies of Silen (1954, Ark. 2001. 6, I-40) and the neuro-biological recordings of Wilson and Bullock (1958, Anat. Rec. 132, 518-519) has been ignored. In the section on feeding, Emig perpetuates the intuitively unattractive and physically impossible (see Strathmann, 1973, Marine Biology, 23, 129-136; Ryland, 1976, op. cit.) suggestion of feeding being largely by impingement.

Perhaps the most useful thing Emig could have done in this review would have been to have used the long section (pp. 71-81) on the relationships and systematic position of the Phoronida to provide a balanced review of this potentially interesting field. However, he has mainly restated his own somewhat idiosyncratic views without any realistic attempt to provide a balanced review of the evidence. His assertion that the lophophorate groups (Phoronida, Brachiopoda and Bryozoa) are related, agrees with the ideas of probably the majority of workers in the field but no alternative view is examined. In particular there should be some discussion of possible bryozoan--entoproct relationships (e.g. Nielsen, 1971, Qphelia 9, 209-341; 1977, Biology of Bryozoans, Academic Press, London). The credibility of Emig’s arguments is surely reduced by his unqualified assertion (p. 79, also p. 2) that phoronids are known since the Devonian. Not a single fossil phoronid of any period has been found and evidence for them in the Devonian consists solely of some fossilized holes for which any of a wide variety of highly speculative origins, including burrowing by phoronids, might be possible. Also surprising is the statement that ‘the common ancestral stock gave rise to the Brachiopoda and Bryozoa as blind branches, then continued along its main line of evolution to the Phoronida’. This ‘main line of evolution’ consists of about ten living species, all very similar, whilst both the other groups contain vastly greater diversity and are more speciose by orders of magnitude.

An example of Emig’s presentation of his case is his statement (p. 71) that ‘it is now

Book reviews 595

generally agreed that the Lophophorata, to include Brachiopoda, Bryozoa and Phoronida, should have phylum status (Emig, 1977, Bull. Sot. 2001. Fr. 102, 341-344).’ With this he presents to the unwary reader as a fait accompli an idea which is highly controversial and which, as far as I know, is not unequivocally supported by any other major worker on lophophorates. Emig also argues (p. 2) that the name Tentaculata of Hatschek (1888, Lehrbuch der Zoologie, Jena) has to be rejected because it is confusing and only his (actually Hyman’s) Lophophorata should be used. This suggests that Tentaculata may be a senior synonym and therefore the name Lophophorata is invalid. In too many cases evidence supporting the author’s ideas is overstated, whilst contradictory information is largely ignored and controversial hypotheses are presented as facts. This presentation is particu- larly regrettable since it is unnecessary; many of his views may well be correct and could be supported by a balanced presentation.

Despite the above criticisms large parts of Emig’s paper provide potentially useful and largely unobjectionable, if somewhat lengthy, reviews of various aspects of phoronid biology. Although there may be some duplication of content with other work, to have all the information available in a single review will always be more convenient. It also provides in a single document a detailed and comprehensive source of references for most of the available literature on phoronids up to about 1980. Whilst the review is open to criticism, many of the faults are presumably the result of inadequate direction or editing by the editors and/or their referees (if any). Even where the author has chosen to present a personal rather than a balanced view, this, I assume, will be in the absence of any direction to the contrary.

‘Coral communities and their modifications relative to past and prospective central American seaways’ by P. W. Glynn is reviewed by B. R. Rosen. The title of Glynn’s review is a fair indication of the cautious style of his text. This belies through its scientific rather than journalistic mode the strongly political and emotive conservation issue of a sea level canal through Panama. Half of the review is headed ‘theoretical’ or ‘speculative’, which is a measure of the difficulty which conservation ecologists have in predicting anything in particular. This state of the art does in one sense make discussion of a sea level canal unnecessary beyond the single phrase ‘don’t’. I imagine that the generating force behind all the scientific output on this subject is the hope by those with vested interests that someone can convincingly be placatory or say what they want to hear. Certainly Glynn wears a troubled frown and is not prepared to do this. Nor would I be.

So why do we apparently waste words on the subject? Presumably because our very uncertainty does have the value of generating ecological questions and research, and this is where Glynn’s review will be of interest to readers. It is a synthesis of what is known about the ecological and bio-geographical distribution of organisms (not just corals, as in the title) on either side of the Central American Isthmus, with extensive documentation. With regard to past seaways I think that Glynn might have mentioned the vicarious view on the biogeographical history of this region notably the work of Donn E. Rosen. Like Glynn, I feel wary of invoking competitive interactions to explain past, present or future community structure. Do we just find competition because we are looking for it? Notwithstanding, all this, here is a good review of the ecology of a potentially even hotter tropical region.

J. P. THORPE

B. R. ROSEN