AN ATTEMPT TO CLASSIFY EARTHWORMS. 233 



gether with the position of the spermathecal pores close to the 

 ventral raid-line, and the general appearance of the worm, 

 warrant the retention of the genus. I may mention here that 

 frequently a mere description of the position of pores and 

 organs, unaccompanied by figures, might lead to the associa- 

 tion of two worms, an examination of which would leave a very 

 different impression as to their relation. 



The genus Deinodrilus is sufficiently interesting and pecu- 

 liar in the possession of twelve setee per somite ; but this interest 

 is greatly enhanced on comparison of the internal organs with 

 those of Acanthodrilus on the one hand and of Perichseta 

 on the other. 



Some species of Acanthodrilus have large nephridia, the 

 power of which alternate in position ; but no statement is made 

 as to whether these nephridia are accompanied by a network : 

 I believe we may expect this to be the case. Many species 

 have the dorsal vessel double to a greater or less extent. 



h. Setae more than twelve (usually many more) in most of 

 the somites, arranged in a ring, which is continuous all 

 round, or interrupted dorsally and ventrally. 



Family III. Perichsetidse, Claus (= partly L. postclitel- 

 liens, E. P. = Perichsetidse + Pleurochsetidse, Vejdovsky). 



Clitellum completely surrounding the body, obliterating 

 entirely the intersegmental grooves, and extending over all or 

 some of the Somites xiii — xvii. 



Spermiducal apertures on Somite xviii, on the ventral 

 surface. 



Oviducal apertures close together on Somite xiv. 



Genus 11. Perich^ta, Schmarda, 1861 (includes Mega- 



scolex, Templeton, 1844; Pleurochseta, Beddard, 1883 ; 



and many of Kinberg's genera). 



Setae from twenty to eighty, or even 100 per somite, on a 



ridge (at least in spirit specimens), either in a continuous ring 



or interrupted by a greater or less gap in the dorsal or ventral 



VOL. XXXI, PART II. -NEW SEK. Q 



