AN ATTEMPT TO CLASSIFY EARTHWORMS. 241 



interesting point in this connection, however, is his descrip- 

 tion of a clitellum in M. sapphirinaoides occupying Somites 

 X — XIII, a structure previously denied to the genus. 



The recorded absence of a clitellum is probably due to the 

 fact that, as in the water-worms, this structure is only deve- 

 loped at the breeding season. 



The anterior gizzard, which Perrier described, has not been 

 recognised in the later species. 



I believe Moniligaster to be more nearly related to the 

 ancestors of earthworms than any other genus we know of, 

 as I have pointed out in Part VI of this paper. 



h. Male pores on Somite xvii or xviii. 



Clitellum occupies all or any of the Somites xiii to xviii. 



1. Eight setse per somite, in couples or separate. 



Family V. Eudrilidse, Claus ( = Lumbriciens intraclitel- 

 liens, E. P., in part=part of family Eudrilidse, Vejdovsky, 

 Rosa) . 



The eight setEe are in couples or separate; the clitellum, 

 complete ventrally, extends over all or some of the Somites 



XIII to XVII. 



The male pores are behind the clitellum, or just within 

 its limits. 



The prostate is simply tubular, convoluted, or lobed. 



Spermathecse usually with diverticulum. 



Typhlosole absent. 



The duct of the nephridium is not produced into a csecum, 

 nor is there any modification of the anterior nephridia. 



Genus 13. Eudrilus, E. P., 1872. 



Setae in four couples. 



Clitellum covers Somites (xiii) xiv to xviii. 



Male pores large, on Somite xvii (from it the curved 

 chitinous penis sometimes protrudes), in line with inner couple 

 of setae. 



