56 W. N. F. WOODLAND 



extend over the greater part of the body length. The two 

 vasa deferentia unite to the left of the middle line at about 

 the level of the hind end of the ovary, the right vas deferens 

 crossing the ovary on its dorsal side. The common sperm 

 duct then runs posteriorly to the left of the vagina, and just 

 anterior to the terminal opening becoines invested by a thick 

 coat of muscular tissue ^ (mtd) and then forms the thick-walled 

 ductus ejaculatorius (dbj). The arrangement of the terminal 

 openings of the ductus ejaculatorius, vagina, and terminal 

 excretory duct in A. paragonopora differs considerably 

 from those of other species of Amphilina and merits careful 

 description. PI. 3, fig. 11 shows the general rather indeter- 

 minate appearance of these ducts as observed in flattened and 

 therefore distorted specimens of A. paragonopora. 

 This figure shows at least that all three ducts possess 

 openings to the exterior which lie very close together (hence 

 the name of the species ' paragonopora ', suggested to me by 

 Dr. Baylis) and which are situated on the small median papilla 

 enclosed in the bay (bay) at the posterior extremity of the 

 body, but to ascertain the exact inter-relationships of these 

 ducts and apertures it is necessary to study series of horizontal 

 and sagittal sections through this region (PI. 3, fig. 12). Such 

 series show (1) that the vagina opens on the dorsal side of the 

 base of the papilla when this is extended (see PI. 3, fig. 1, /) ; 

 (2) that the opening of the ductus ejaculatorius to the exterior 

 is terminal on the papilla (pe) ; and (3) that the opening of 

 the terminal excretory duct (ted) is also terminal on the 

 papilla and lies, so far as I can ascertain from sagittal sections 

 and flattened whole-mount specimens, just to the left of the 

 opening of the ductus. In some specimens the opening of the 

 excretory duct appears to be confluent with that of the ductus. 

 Thus all three openings lie very close together — so close that 

 for a long time I thought they were all confluent. I may add 

 that the excretory duct is situated ventrad to the ductus 

 ejaculatorius where the former crosses the latter, and that 



^ This is commonly called a ' prostate gland ', but there is certainly no 

 evidence of its glandular nature in my preparations. 



