The Classification and DistrihiUion of Earthvjorms. 261 



group are so great, that it is requisite to divide it into several 

 families. 



1. Family Urochaetidse. 



Setm irregular in distribution either throughout the whole 

 body or after the first 1 segments or so. Prostomium 

 absent. Spermathecoe, three pairs. Calciferous glands, 

 three pairs. Ne'phridia with sphincter.^ A mucous 

 gland 2)resent, being 1st nephridiwm. 



Genera — Urochmta, E. P.; Diachceta, Benliam ; Onycho- 

 chceta, F. E. B. 



2. Family GeoscolecidaB. 



Setae paired or distant {both conditions occurring in the 

 same species) ; prostomiurri present. Nephridia all alike. 



Genera — Geoscolex, Leuck. j Hormogaster, Jxohsl ; ? Glyphi- 

 drilus,^ Horst. 



3. Family Rhino drilidae. 



Setoi paired or distant. Anterior set of nephridia different 

 from posterior. 



Genera — Microchoita, F. E. B. ; Brachydrilus, Benham ; 

 Urobenus, Benham ; jRhinodrilus, E. P. ; ? Anteus, E. P.^ 



I do not regard these families as in any way so satisfactory 

 as those of the Acanthrodrilini. 



The Urochsetidae is perhaps the best and most natural. I 

 am quite prepared to admit that the two last might possibly 

 be with advantage broken up still further. 



^ I apply this name to the little muscular cup first described by Perrier, 

 loc. cit. (on p. 255), which surrounds the extremity of the muscular sac of 

 the nephridium. 



^ At present our knowledge of this evidently very interesting form is con- 

 fined to the briefest of abstracts given in the Proces Verbal of the Dutch 

 Zoological Society (Nederl. Dierh. Ver. Verslag der Vergadering vam 26 

 October 1889, p. 1). 



^ I have already pointed out (On the Structure of a new Genus of 

 Lumbricidai, Thamnodrilus Guliehni — P. Z, S., 1887, p. 154) the resemblances 

 between Anteus and RMnodrilus. I should not be at all surprised to learn 

 that they are congeneric. 



