272 FEANK E. BEDDAED. 



todrilus differs from the Eudrilidse : the first is the position 

 of the nephridiopores, which are situated in front of the ven- 

 tral instead of the lateral setae ; the second character is the 

 absence of any glandular diverticula to the alimentary tract. 



To these I can add a third character — the absence of those 

 integumental bodies which occur in all other Eudrilidee that 

 have been sufficiently well examined. 



The structure of Nemertodrilus shows that it is deci- 

 dedly an aberrant member of the family Eudrilidse. But the 

 alterations in structure from the typical Eudrilidse do not de- 

 finitely point in the direction of the Cryptodrilidae, with which 

 family, as I distinguish it, Rosa unites the Eudrilidse. 



The only reasons for referring this genus to the Eudrilidae 

 are (1) the absence of spermathecse lying in front of the testes, 

 (2) the completely separate vasa deferentia opening into the 

 interior of the atrium, (3) the large coelomic sacs connected 

 with the egg-sacs, (4) the muscular oviduct. 



The absence of any specialisation into the atrium, of dilata- 

 tion upon the vasa deferentia, of integumental organs, are 

 perhaps indications of degeneration. The fact that the ovary 

 is not, as is the rule among the Eudrilidse, enclosed in a special 

 compartment of the coelom, might be used as an argument for 

 the primitive position of Nemertodrilus among the Eudri- 

 lidae were it not for the reduction of the cavity of the thirteenth 

 segment. The reduction of this segment renders the develop- 

 ment of any such sacs unnecessary, though of course it does 

 not necessarily follow that they were originally present and 

 have been lost. On the other hand, the pores upon Segment 13, 

 whether Michaelsen^s explanation of them or mine be correct, 

 seem to be in all probability rudimentary structures of some 

 kind. 



London ; September 9th, 1890. 



