PHYLUM ANNELIDA 



203 



entia coming from the vesicles on each side forms a single pair of 

 vasa deferentia in segment XII. The seminal receptacles are pairs 

 of small white bodies located in segments IX and X. The ovaries 

 are two minute bodies located one on each side of segment XIII. 



Digestive System 



The mouth cavity extends through segments I to III and leads 

 into the bulbous, muscular pharynx which extends through segment 

 V. The pharynx plays the part of a sucker in securing food for 



Fig. 104. — Diagram of dorsal dissection of an earthworm in region of segments 

 I to XXI. be, buccal cavity ; eg, calciferous glands ; cr, crop ; dv, dorsal blood 

 vessel ; eo, esophagus ; g, gizzard ; n, nephridium ; sb, subpharyngeal ganglion ; st, 

 stomach-intestine ; pe, peristomium ; II-XXI, somites ; pJi, pharynx ; pr, prostomium. 

 (From White, General Biology.) 



the animal. The esophagus is a straight narrow tube extending from 

 the pharynx through the fourteenth segment. In segments X to XII 

 three pairs of yellow lateral pouches open into it. These are the 



