STRUCTURE OF EARTHWORM ALLIED TO NEMERTODRILUS. 683 



five segments and lodges receptacula ovorum ; oviducts pass 

 from these to apertures on 15th segment. Atria two, with 

 thick muscular walls opening by a common orifice on middle 

 line between Segments 17, 18. Each is furnished with a 

 single penial seta. Vasa deferentia without dilatations or 

 muscular coat, open near to summit of atria. CEsophagus 

 without calciferous glands or ventral pouches ; three gizzards 

 present at end of oesophagus in Segments 23, 24, and 25. 

 Integument without sense bodies. 



Libyodrilus violaceus, F. E. B. 



Setae strictly paired and ventral in position. Penial setee 

 short with a rounded free extremity. Clitellum occupying 

 three segments (14 — 16). Dorsal vessel single. Colour dark 

 violet with a tinge of pink. 



Habitat — Lagos, West Africa. 



The above definitions must in the present state of our 

 knowledge be regarded as only tentative. 



VIII. Summary. 



The principal new facts in this paper may be briefly sum- 

 marised as follows : 



(1) The nephridial system consists of paired nephridia 

 which do not open immediately on to the exterior, but are 

 connected with an extensively ramifying system of tubes 

 embedded in the circular and longitudinal muscular coats; 

 these tubes consist of four principal longitudinal trunks con- 

 tinuous from segment to segment, and of a single large cir- 

 cular vessel in each segment passing right round the worm at 

 the junction of the circular and longitudinal muscles ; these 

 are connected by a plexus of vessels, and numerous tubules, 

 leading to the exterior, are given ofl" from the circular trunk. 

 In some of the genital segments the paired nephridia have 

 almost disappeared, leaving only the integumental network. 

 Nothing of the kind has been yet described in any Oligochaete. 

 In the young worm, just escaped from the cocoon, there is no 



