314 PROC. COTTESWOLD CLUB vol. Xlll. (4) 



" In Rhynchelmis the two nerves, although lying close 

 together, are quite distinct as two nerves. They are not 

 present in the middle segment. 



" In Rhynchelmis, Vejdovsky could only find a single 

 pair ; three pairs is a much more usual number. 



''Respiratory System: — In the great majority of Oligo- 

 chceta there are no special respiratory organs — the general 

 body-surface occupying the place of a lung or branchia. 

 When the integument is thick there are ahvays plexuses of 

 blood capillaries in the integument which bring the vascular 

 system into close relations with the external medium, and 

 presumably allow an exchange of gases. The blood is in 

 all Ohgochceta, with few exceptions, tinged with hoemo- 

 globin. 



" Reproductive System : — The Oligocheeta, like some 

 other animals which are hermaphrodite, possess a compli- 

 cated series of organs, related to the reproductive system. 



" The essential organs are the ovaries and testes — the 

 gonads — which are developed from the peritoneal epithe- 

 hum, and are nearly always paired structures, and are pre- 

 sent in all Oligochceta. 



"The ovaries are usually a single pair ; but there is some- 

 times an additional pair. The ovaries invariably agree in 

 position with the -testes, but they are of course situated 

 in different segments. The ovaries always lie behind the 

 testes. In Rhynchelmis the testes are contained in segments 

 ix, X, and the ovaries in segment xi ; the male pore in 

 segment x, the oviducal pores in segments xi, xii. The 

 gonads are the first part of the reproductive system. The 

 various organs, essential and non-essential, have fixed posi- 

 tions in the body of the worm ; one organ is found always 

 in one segment, another in a second segment, in every 

 species, the position being characteristic of the species, or 

 genus, or family, as the case may be. 



