Different species of Annelids

By NOMAN KHAN

Phylum Annelida• Annelida is a latin word which means ring so these

worms are also called ring worms.

• There are about 15000 species.

• They are triploblastic ,coelomate and bilaterally symmetrical.• locomotory organs are parapodia or chaetea /setae

(small hair like structures)• Excretion occurs through nephridia.

• They have closed circulatory system and no

respiratory organ . ( general surface/gills).• They are hermaphrodite.• This phylum have 3 classes.

• 1)Class Polychaeta • 2)Class Oligochaeta• 3)Class Hirudinae

Class polychaeta • Poly means many and chaeta maens seta so they • have many chaeta .

• This class includes Neries and Sabella species .....

Neries

Neries• They are found in marine water.• Their body is elongated and metamerically

segmented.• Their head is distinct called prostium which possess

eyes tentacles,antennae and bristles or palps.• Sexes are separate and fertilization is external.• Locomotion takes place by parapodia.

• Resiration occur through gills under parapodia .

Class Oligochaeta • Oligo maens few and chaeta means seta so they

have few chaeta or setae ..

• This class include earthworm

Earthworm /pheritema posthuma

Earthworm• An earthworm is a tube shaped segmented worm.• It is found either in soil on soil surface .• It is nocturnal and feed upon small food particles

and organic matter.• Its body is metamerically segmented (about 100 to

several segments)......

Earthworm• Locomotion take place by setea annd paapodia is

absent. They are hermaphrodite... They are segmented metamerically externally by transverse grooves and internally by tansverse muscular partitions called septae into a number of divisions called somites,metameres or rings.

Class Hirudinea• The members of this class do not have any

cheata ...

• Leech are included in this class

Leech /Hirudinaria

Leech • It lives on the outer surface of their host and are

ecto parasites

• Its body consists of definite number of segments i-e 34 .

• Body is elongated and flattened.

• They donot have chetae or appendages ..

• Reproduction is sexual.They are hermaphrodite .They are blood suckers They are used in treatment as tbey secrete anti clotting enzyme Hirudin during blood sucking.

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• Thank you ............