6 EARTHWORMS AND THEIR ALLIES [ch. 



on each of the segments xvn, xvm, xix are a pair 

 of pores of which those on the xvinth segment are 

 the least conspicuous. The large pair of pores on 

 each of segments xvn and xix occupy the position 

 of the ventralmost pair of setae, which are here 

 absent, or rather replaced by a very long curved and 

 ornamented seta, which projects out of the orifice. 

 These two pairs of pores are the outlets of the 

 prostatic glands as they have been termed. The 



Fig. 4. The same species. Ventral view of segments xvi-xx 

 (numbered in the figure) which form the clitellum, the posterior 

 boundary of which is shown by a curved line on segment xx. 

 The figure will be understood from the annexed description. 



minute pair of pores on segment xvm do not take 

 up the position of the ventral setae ; for these are 

 present and to the inside of each pore. A groove, 

 shaped something like a reversed 3 or the Greek letter 

 2, connects the orifices of each side of the body, the 

 middle part of the groove, where the two semicircular 

 halves of which it is composed meet, coinciding with 

 the minute pores on segment xvm which are the 

 orifices of the sperm ducts. 



