Ceylon and the Philippine Islands. 91 



by an inspection of fig. 3 ; the distal and proximal ends are 

 slightly curved and convergent, while the middle portion is 

 straight ; the distal extremity of the seta which protrudes 

 through the orifice ends in a sharp point and is furnished 

 with a series of minutely serrated ridges which are at first 

 regular, but as they approach the tip become broken up ; 

 fig. 3 «, which is a highly magnified representation of this 

 portion of the seta, shows its characteristic form and is better 

 than any description. It is only the distal one fourth of the 

 seta which is thus ornamented ; the ridges gradually disappear 

 behind. 



In front of the aperture through which protrude these 

 penial setai, and therefore close to the anterior limit of tlie 

 segment, is another pair of apertures (fig. 1, «), approximately 

 in the same straight line with the posterior orifices. The 

 two apertures of each side of the body are situated upon a 

 flattened area differing somewhat in its appearance from the 

 rest of the integument. The internal structures corresponding 

 to these apertures are peculiar : the anterior pair of orifices 

 lead in each case into a long somewhat coiled tube, ending 

 cffically and of uniform diameter throughout (fig. 2, a) ; with each 

 of the posterior pairof apertures isconnected a large brown gland 

 (fig. 2, h) , divided by deep furrows into a multitude of minute 

 lobules ; this prostate gland opens to the exterior by a long 

 somewhat curved muscular duct ; on the left side of the body 

 the gland extended through five segments, commencing with 

 and including the eighteenth ; on the posterior side of the duct 

 of the prostate gland is a thin-walled sac (c) containing the 

 penial setse already referred to. I am unable to state the rela- 

 tions of the vasa deferentia to these two glands, since they, as 

 well as the testes, could not be recognized. 



With the exception of a single species described by myself * 

 no PerichcBta is known which possesses these peculiarly 

 modified penial setse; they are, however, characteristic of 

 other genera (e. g. Acanthodrilus, Eudrilus, Typhoeus)^ and 

 present more or less the same form in all, differing widely from 

 the ordinary setse of the body. 



The complication of the prostate glands in Perichceta cey~ 

 lonica is a new feature in the organization of this or any 

 other genus. 



A multifid prostate gland, like the posterior gland of P. 

 ceylonica, is characteristic of the genus Perichceta and is found 

 in all species of the genus with but trifling modification in 

 shape, depending upon the more or less complete lobulation of 



* P. armata, Anu. & Mag-. Nat. Hist. 1883, p. 216. 



