gg TEE BIOLOGY OF AN ANIMAL. 



Besides the lateral vessels from the sub-neural and supra-neural a pair 

 of ventro-lateral" (v.L, Figs. 26 and 27) are given off in each somite from 

 the sub-intestinal to the nephridium, probably receiving from it the blood 

 originally entered through a branch of the dorso-tegurnentary. 



>CQS 



FIG. 27. Nephridia of LMmhricu*. A showing the regions of the tube, B the vascular 

 supply. /, II, III, the three principal loops. 



A. /.funnel; i.f, the "narrow tube"; m.f, middle tube; u\f, wide tube: m.p, mus- 

 cular tube or end-vesicle ; cte, dissepiment. The narrow tube extends from a to Q 

 and is ciliated between a and b, at c, and from d to c. The middle (ciliated) tub0 

 extends from g to /i , the Vide tube from h to /c, where it opens into th muscular 

 part ; r, external opening. 



B, Letters as before ; d.t, dorso-tegumentary vessel, bringing blood ft om the dorsal 

 vessel, receiving at s a branch from the body- wall, sending an afferent branch to 

 the nephridium., and finally joining the sub-neural (.); r.f, ventro-lateral vessel 

 carrying the blood from the nephridium to the sub-intestinal or ventral vessel 

 (s.i) ; r.w, ventral nerve-cord. (After Benham ; the direction of the blood-cur- 

 rents according to Bourne.) 



Excretory System. It is the office of the excretory 'system to 

 remove from the body proper the waste matters ultimately re- 



