646 OLIGOCHAETA 



Sparganophilus tamesis, BENHAM. 

 S. tamesis, BENHAM, Q. J. M. S., vol. xxxiv, 1893, p. 155. 



Definition. Length, three or four inches. Setae strictly paired, ornamented. Ann* dorsal 



in position. Hal. River Thames. 



The worm occurs in the Thames; it is said by BENHAM to be firm to the touch, 

 and to wriggle violently when handled. The cocoon is rather elongated and sausage- 

 shaped, somewhat as in Criodrilus. 



Genus TRICHOCHAETA, BEDDARD. 



DEFINITION. Setae paired or scattered, ornamented at tip with numerous spinelets. 



Prostomium long and retractile. Calciferous glands small and rudimentary. 



Testes and sperm-ducts one pair. Sperm-sacs very long, with numerous short 



branches posteriorly. 



This genus, which is exclusively West Indian in habitat, contains two species ; 

 both of these have been described by myself in two recent memoirs (39, 57). The 

 peculiar form of the setae absolutely distinguish the genus from any allied form ; 

 they have the usual ./-shape, but at the free extremity the seta is covered by a great 

 number of minute spinelets which give this part of the seta a roughened appearance ; 

 as the fine points of these spines are apt to get worn off, the rough appearance 

 is sometimes alone left. In one species of the genus (T. hesperidum] the setae are as 

 in Pontoscolex and Diachaeta scattered ; in the other species (T. barbadensis) the 

 setae are strictly paired throughout, showing no traces of the irregular arrangement ; 

 this fact might be regarded as a reason for separating the two species in question 

 generically ; the case of Pontoscolex seems to render this unnecessary ; it will be 

 remembered that in the species P. corethrurus there are individuals which have 

 paired setae, though in the great majority of individuals the setae are, after the 

 first few segments, irregular in disposition. The prostomium has a considerable 

 length, and it is, as in the genus Rhinodrilus, retractile within the mouth-cavity. 

 The clitellum is complete, at least in T. barbadensis; in the second species of the 

 genus the clitellum is unknown ; a complete clitellum is rare in the family 

 Geoscolicidae ; the only other instance is P. trinitatis. 



The position of the apertures of the male pores is unusually far back in 

 T. kesjjeridum on the twenty-fourth segment. 



