648 OLIGOCHAETA 



occupying segments XIII-XXII. Rudimentary oalciferous glands in VII, Fill, IX. 



Spermatkecae in IX, X, XL Hal. Barbadoes. 



This species has not the enormously elongated sperm-sacs of the last ; at any rate, 

 the single example examined by myself had not. They extended only through five 

 or six segments. The funnels of the sperm-ducts are very large ; they nearly reach 

 the testes in front and end just in front of the septum bounding segments xiii/xiv ; 

 they lie within the sperm-sac. The oviducal pores lie in the groove between segments 

 xiv/xv ; in T. hesperidum these pores lie within the ventral pair of setae. The 

 sperm-duct does not open so far back as in the latter species ; it appears to open 

 on to the seventeenth segment. 



Genus ONYCHOCHAETA, BEDBARD. 

 Syn. Diachaeta, BEDDARD. 



DEFINITION. No prostomium. Setae absent on the first five segments, scattered 

 from the commencement. Mucous gland present; calciferous glands repre- 

 sented by a swelling of the intestine with folded walls, occupying segments 

 XIII-XIV. Two pairs of testes, ciliated rosettes and sperm-sacs. 



This genus is, at present, only known from a single species investigated by myself. 

 The most remarkable character, which distinguishes the genus from its allies, 

 Pontoscolex and Diachaeta, is the arrangement and structure of the setae. Their 

 absence from the first few segments of the body is not a peculiarity of the genus ; 

 it is met with in the genera Tykonus and Kynotus. Nor is the fact that the setae 

 are irregular in disposition unique ; scattered setae characterize Pontoscolex, Diachaeta, 

 and the little known genus Geogenia; moreover in Diachaeta we have this scattered 

 condition apparent from the first segment which has setae, as in the present genus. 

 What is chiefly remarkable about the setae of Onychochaeta is that they are not 

 arranged in the first three segments upon which they occur at any rate in 

 a regular transverse ring. They are in the segments referred to disposed in two 

 distinct rings, a possibly commencing division of the segment into two. The setae 

 are of two kinds as is usual in this family. There are simple sigmoid setae 

 without any ornamentation, and longer and at the same time ornamented setae. 

 As a general rule the ornamented setae, when present in addition to simple 

 unornamented setae, are confined to the clitellum ; this is, however, not the case 

 with the genus Onychochaeta. On the first few segments of the body the setae are 

 all of the larger ornamented kind. After the tenth segment these setae also occur, 



