140 PROCEEDINGS OF THE ACADEMY OF [March, 



fully, but in no instance was there a trace of jaws, radula or distinct 

 salivary glands. 



Posterior to the central nervous system the lining of the pharynx 

 becomes smoothed out before uniting with the smooth-walled 

 stomach. Externally there are no noteworthy features to be noted 

 in this section of the gut. It may be said, however, that the stomach 

 is somewhat shorter than the pharynx and of considerably greater 

 diameter. On the left side of the stomach are two sac-like dilations 

 and one on the left, all of which are in communication with ducts from 

 the digestive gland. In sections the lining epithelium of each of 

 these sacs is seen to be thrown into a few high folds that are more 

 or less continuous with lower longitudinal ridges extending throughout 

 the main hepato-pancreatic duct. 



As noted previously, the ventral gastric surface is longer in an 

 antero-posterior direction than the dorsal, and the intestine is thus 

 inclined dorsally, forming a distinct dorsal cleft between the stomach 

 and intestine. Beyond this point the gut proceeds posteriorly, 

 sinking slightly toward the ventral surface of the body, and also 

 curving to the right until it reaches a point on the right side of the 

 animal near the middle of the body. Here it curves dorsally, and 

 expanding considerably opens to the surface. The intestinal epithe- 

 lium is fashioned into several folds, visible externally through the 

 thin wall, of which one, the dorsal, is highly developed and continues 

 like a typhlosole throughout the entire length of the gut. 



In preserved material the yellowish digestive gland is seen through 

 the translucent body wall in the form of a dense mat generally dis- 

 tributed throughout the body, penetrating the lappets and extend- 

 ing into the snout as far forward as the tentacles. As can be seen 

 in the figures, the follicles are united by an extensive system of 

 ducts, which finally communicate with the stomach by means of 

 one of the three openings noted previousl3^ 



The circulatory system can be disposed of in a few words, as the 

 sinuses are unusually delicate and difficult to follow. The pericar- 

 dium (PI. XIII, fig. 13), situated anterior to the rectum, is a spacious 

 thin-walled sac, with the ventral and posterior surfaces largely con- 

 cealed by a mass of excretory tubules. The heart comprises an 

 auricle and ventricle with their longitudinal axes directed in a dorso- 

 ventral direction. The aorta, leaving the dorsal margin of the 

 pericardial cavity, extends forward and soon disappears. On the 

 other hand, the sinuses entering the auricle have been traced into 

 the kidney and to a much less degree into the reproductive system 

 and liver. 



