452 OLIGOCHAETA 



The principal characteristic of the genus is, of course, the fusion into a single 

 median series of the spermathecae. 



About the same time I had myself suggested the desirability of separating 

 MICHAELSEN'S C. purjmreus into a distinct genus. 



Previously to both of us FLETCHER had also surmised that it might ultimately 

 be necessary to take this step. ' These three species,' he remarks, ' form a group of 

 closely allied forms whose claims to be regarded as worthy of generic separation 

 will be considered hereafter.' 



I shall here adopt the generic name of Fletcherodrilus for the species of 

 Cryptodrilus with median spermathecae and male pore. 



There can be no doubt, I think, of the validity of my genus Millsonia, from 

 Western Tropical Africa, unless indeed it should include the African Dichogaster. 



Another genus of which the exact position is perhaps a matter of doubt is 

 Plutellus j this was originally described by PERKIER twenty years ago. More 

 recently BENHAM has met with what he believes to be a second species of the 

 genus, and has suggested that there may be some errors in PERRIER'S account of 

 Plutellus heteroporus ; there is no doubt that if PERRIER'S description is accurate in 

 every particular the species named by him P. heteroporus is not congeneric with 

 BENHAM'S P. perrieri; accepting BENHAM'S corrections as probable, it is not an easy 

 matter to distinguish Plutellus from Megascolides. 



I abstract from BENHAM'S list of the chief characters of the genus the following : 



(1) Setae in eight rows. 



(2) Clitellum complete, xiii-xviii. 



(3) Male pores on xviii. 



(4) Nephridiopores alternate. 



(5) Testes in x ; sperm-sacs in xi ; spermiclucal glands tubular. 



(6) Spermathecae, four pairs without diverticulum. 



(7) No calciferous glands. 



P. heteroporus differs in (6) and (7); there are three pairs of calciferous glands, and 

 the spermathecae have a diverticulum. 



The above enumeration of the chief characters of Plutellus does not permit of a 

 very distinct separation from Megascolides. Indeed, there is no character that is 

 quite decisive in the matter. I do not, therefore, see my way to accepting the 

 genus Plutellus at all, that is to say as amended by BENHAM ; it may be that 

 PERRIER'S original description may prove to be more accurate than it has been 

 supposed to be ; in this case the genus Plutellus will stand. 



