24 



JFirst Annual Report 



along the sides, partially covering the oviducts and ovaries, the 

 middle lobe extending mesially an equal distance, then lapping over 

 the left side, covering the stomach. The alimentary canal is very 

 definitely divided into oesophagus, stomach, pyloric tract, spiral 

 valve (or colon), rectum and cloaca. Both spleen and pancreas are 

 well developed, the former lying along the right side of the stomach, 



Figure 2a. Young Rhinobatus productus 



the latter fastened to the intestine at the anterior end of the colon. 

 The spiral valve in this species makes eleven complete turns, the bore 

 in the first two or three being quite large, after which it is uniformly 

 small to the end where it broadens out considerably in the rectum 

 and still more in the cloaca. Exactly even with, and below the open- 

 ing of the colon into the cloaca is the similar oviducal aperture, a 

 single aperture since the two oviducts coalesce just before reaching 



