2-76 PHYLUM ANNELIDA 



the terminal part or rectum. This rectum, running 

 between the two last pockets, is separable from the true 

 stomach just mentioned by a closing or sphincter muscle. 



It ends in a dorsal anus 

 above the hind sucker. 



Vascular system. — 

 Two main lateral vessels 

 run longitudinally, one on 

 each side of the body. They 

 are connected with one an- 

 other by looping vessels, 

 give off numerous branches 

 which riddle the spongy 

 body, and have a definite 

 muscular coat. On the 

 dorsal surface and ventrally 

 around the nerve-cord are 

 two lacunar spaces, which 

 are really portions of the 

 true body cavity, and not 

 parts of the vascular system. 

 With those and similar 

 spaces, however, the blood 

 vessels are connected by 

 means of a secondarily de- 

 veloped series of canals, 

 roughly corresponding to 

 the lymphatic vessels of 

 Vertebrates. The blood is 

 red, and contains colour- 

 less floating cells of 

 diverse form. 



Fig. 149. — Dissection of leech. 

 — After Bourne. 



e.g., Cerebral ganglia ; p., penis; s.v. 

 is opposite the seminal vesicle ; ov., 

 ovary ; ut., uterus ; v.d., vas de- 

 ferens ; l.b.v., lateral blood vessel ; 

 r.4, fourth testis ; n.v., nephndial 

 vesicle ; N.17, last nephridium ; 

 G.19, nineteenth pair of ganglia; 

 n.c, nerve-cord. 



I6v 



n.c 



