On some Periclisetidae from Japan. 7g5 



sitle of the body, therefore, this worm agrees wiht Ferichceta rokugo, 

 and 011 the other with cither P. sieboldi or some nearly related form. 



Remarks upon the Japanese Perichcetce. 



As will be seeu from the foregoing descriptions as well 

 as from previously published descriptions, so far as they relate to the 

 points in questiou, the species of Perichceta found in Japan show 

 certain peculiarities, which distiuguish them. 



In all there is au absence of seta3 from the clitellar Segments; in 

 niost of them there are capsulogenous glands in the immediate 

 neighbourhood of the spermatothecse, which are borne on long stalks ; 

 in several of them there is a tendency for the atria to become 

 rudimentary, which tendency culminates in P. rokugo; in this species 

 the atria have entirely vanished, leaving not a trace behind. Finally 

 the receptacula ovorum are almost always a Single pair, situated — 

 a raost unusuai position, when there is but a Single pair — in Seg- 

 ment XIII. 



The most important of these divergencies from the normal 

 structure of the genus is undoubtedly the disappearance of the atria, 

 associated with the alteration in the position of the male orifice. This 

 character is a step in the direction of the Geoscolicidm ; but there 

 are no other indications of an atfinity in this direction. The 

 peculiarities of the Japanese Perichcetidce are not universal enough 

 among the species to allow of their being used to separate these 

 forms as a distinct genus. 



