260 Proceedings of the Royal Physical Society. 



It results from the above table that our knowledge of this 

 group is still very incomplete. There are many gaps which 

 require filling up. There appear to be, however, a number 

 of characters in which all the genera agree, many of which 

 .have been already mentioned by Eosa. These are as 

 follows : — 



(1.) Paired nephridia. 

 (2.) Absence of atria and of penial setse.^ 

 (3.) Spermathecse without diverticula. 

 ? (4.) Absence of dorsal pores. 

 (5.) Gizzard (or Gizzards) anterior in position. 

 (6.) Generative pores withip the clitellum. 



Considered individually these characters are not, perhaps, 

 very important. There seem to me to be no good reasons 

 why any one of them should not have been independently 

 acquired more than once. 



Seeing, however, that they occur in all of a number of 

 , genera, which are also interconnected in other ways, it is, in 

 my opinion, necessary for the present to retain this group, 

 which I term 



Group IV. GEOSCOLECINI. 



Definition. — Eay^thworms with paired nephridia ; never 

 furnished with atria or penial setce {? Rhinodrilus). 

 Clitellar setce often modified; spermathecm without diver- 

 ticula. No dorsal pores. Gizzard (or gizzai^ds) anterior 

 in position. Setce 8 in each segment, paired or distant, 

 or irregular in their arrangem,ent. Male pores within 

 the clitellum. 



The differences between the genera which make up this 



^ Horst has described (Descriptions of Earthworms, I, — Notes Leyd. Mus., 

 1887, p. 101) in Rhinodrilus tenkatei the remarkable fact that " the ventral 

 setae of the 17th, 18th, and 19th segments were replaced by a fascicle of 

 four bristles." This is suggestive of the persistence (and multiplication) of 

 penial sette, and appears in any case to be a particular point of resemblance 

 to Pliotodrilus, in which worm Giard (Sur uu nouveau genre de Lombriciens 

 phosphorescents, etc. — Comptes Rendus, Nov. 7, 1887) has recorded similar 

 structures. 



