THE ELASMOBRANCH FTSIIES 291 



of the most aiitoi-ior of these are united with the central canal of the testis, 

 and the tubes pass down over the uiesorchium and join the upper part of the 

 coiled vas deferens. 



The vas deferens in Heptanehus is very simple in that it is a single con- 

 voluted tube which increases only slightly in size l)ack to the anterior tip of 

 the ureter. From here it passes backward in the immature specimen more or 

 less as a straight tube. After having received the ureter, as we have seen, it 

 enters the urinary sinus. Since in the adult this urinary sinus also receives sex 

 cells from the vas deferens it becomes a urogenital sinus in the male. The 

 spermatozoa and the fluid collected in the urogenital sinus are forced through 

 the papilla and out through the cloaca. As they leave the cloaca they are di- 

 rected through a groove on the clasper and may be transferred to the cloaca 

 of the female. 



In a number of immature males examined, right and left rudimentary ovi- 

 ducts were present. These were united at the midventral line and had a com- 

 mon funnel as in the female. In all the specimens examined, however, they 

 were of short extent, all of them ending blindly posterior and being attached 

 to the body wall anterior to the segment of the shell gland. 



