I9I7-] J- Stephenson : Indian Oligochaeta. 391 



developing spermatozoa. There are two pairs of seminal vesicles, 

 both of moderate size and both slightly lobed in outline • the 

 anterior are in segment ix, attached to septum 9/10, the posterior 

 in xii attached to 11/12. 



The prostates are two pairs, together extending from segment 

 xvii to XXV. Each is a long and convoluted tube thrown into a 

 number of loops in each segment through which it passes. The 

 posterior, after occupving segments xxv-xxii, suddenly in segment 

 xxi, becomes thin, — a quarter of its former diameter; and so con- 

 tinuing through XX, becomes in xix a fusiform shining muscular 

 tube, which turns obliquely inwards to end near the middle line at 

 the anterior border of the segment ; the thickest part of the duct 

 (the fusiform swelling near its termination) is about as wide as the 

 main portion of the gland. The anterior prostate begins on each 

 side in sesjment xxi, thus overlapping the thin anterior portion of 

 the posterior gland ; it maintains its initial thickness through xx 

 and xix, becomes thin in xviii, and the fusiform duct, of the same 

 character as that of the posterior gland, curves inwards in xvii to 

 open near the middle line at the hinder border of the segment. 



The vas deferens comes down on each side to join the end of 

 the ducts of the anterior pair of prostates on their outer sides. No 

 such arrangement can be seen in connection with the posterior 

 prostates. 



Underneath the prostatic ducts in segments xvii and on the 

 right side in xix, and therefore corresponding to the sucker-like 

 depressions seen externally, are circular white cushions or eleva- 

 tions of the body-wall. This region (segments xvii, xviii and xix in 

 their ventral portions) is characterized by dense clusters of 

 micronephridia, which however are absent from the circular 

 cushions just mentioned. 



The ovaries are in segment xiii. 



The spermathecae are two pairs ; the ampulla is sac-like, 

 broadly ovoid with pointed tip ; the duct is broad and short, and 

 not set off from the ampulla, of wliich it is merely a narrower con- 

 tinuation. There are numerous diverticula, about fifteen to a 

 score, arranged as a complete circle round the lower part of the 

 ampulla ; each is a small rounded protuberance, broadly sessile 

 (fig. 14). The ducts of the anterior pair of spermathecae run back- 

 wards under the peritoneal and connective tissue layers of the body- 

 wall, becoming narrower as they do so, and ultimately pierce the 

 parietes not far from the middle line at about the middle of the 

 length of segment viii ; this corresponds with the surface-marking 

 previously described. 



A number of accessory glands are associated with the sperma- 

 thecae. These project into the coelom near the spermathecal 

 apertures, are cluVj-shaped in general form, and about a millimetre 

 or a little more in length ; they are not hollow diverticula from the 

 base of the spermathecae, but solid masses of cells. A large 

 nephridial tube is closely associated with each spermatheca ; and 

 in addition there are copious micronephridia all round them. 



