DESCRIPTIONS OF GENERA AND SPECIES 649 



but they are mingled with simple small unornamented setae. These latter gradually 

 come to be the only ones present, and towards the end of the body their extremity 

 gets to be more pronouncedly hooked. At the tail end the setae, while still preserving 

 to some extent the character of the setae in the middle region of the body, are 

 enormously enlarged; their extremity is very hooked, and possibly, as I have 

 suggested, serves to hold fast the body of the worm in the ground. 



The nephridia of this genus are, on the whole, similar to those of Pontoscolex ; 

 they agree in possessing a terminal sphincter at the point of opening on to the 

 exterior. 



Onychochaeta windlei, BEDDARD. 



Diachaeta Windlei, BEDDAKD, Q. J. M. S., vol. xxxi, 1890, p. 159. 

 O. Windlei, BEDDARD, P. R. Phys. Soc., 1890, p. 259. 



Definition. Length, 100 mm. Clitellum commencing at segment XV. Gizzard in VI. Two 

 pairs of hearts in X, XL Three pairs of spermathecae in VII, VIII, IX. Hob. Bermudas. 



I have nothing to add to the above definition, as the principal characters have 

 been already described under the genus. 



Genus ILYOGENIA, BEDDARD. 



DEFINITION. Setae paired. Clitellum, XII -XIX. Male pores on XVII. Gizzard 

 absent ; calciferous glands, one pair in IX Spermathecae, one pair in IX. 



This genus consists of only a single species, which, unlike any other member of 

 the subfamily Geoscolicinae, inhabits Africa. It is evidently in some particulars 

 in a degenerate condition as compared to other allied genera ; this is shown not 

 only by its small size, but by the fact that the nephridia do not terminate, as they 

 usually do, in a muscular sac, but open directly on to the exterior without the 

 intervention of such. They open, too, in front of the ventral pair of setae. From 

 the eighth or ninth segment onwards the nephridia are invested by a thick sheath 

 of clear non-staining pyriform cells. The presence of septal glands from the fourth 

 to the seventh segments connected by a fibrous strand on each side of the body is 

 another point of agreement with some of the lower Oligochaeta. The intestine 

 begins in the twelfth segment. The calciferous glands of segment ix arise ventrally 

 from the oesophagus and are of considerable size, though confined to their segment. 

 The luinen of these glands is much subdivided by trabeculae. Both the supra- 

 intestinal and subnervian vascular trunks appear to be absent ; the last pair of hearts 



4 o 



