70 H. HEATH and M. H. SPAULDING, 



Stomach. Numerous muscles, situated chiefly on the outer surface of 

 the stomach, send slips through the abundant connective tissue beneath 

 each tooth and attaching to its base produce the movements necessary 

 for the trituration of the food. As Peck has shown for Corolla (Cym- 

 huUopsis) calceola each tooth is roughly pyramidal in shape, hyalin in 

 ai)pearance and in general structure much like the substance com- 

 posing the casque. 



The slender intestine, of about even calibre throughout, leaves 

 the posterior surface of the stomach and turning abruptly to the right 

 encircles the visceral mass to open into the mantle cavity somewhat 

 to the left of the median line. 



The most conspicuous part of the alimentary canal is the liver 

 whose bulk equals that of all the other organs of the visceral mass. 

 Its duct, very short, wide and symmetrically placed, leads from the 

 junction of the stomach and intestine into the digestive gland and 

 expands into an' extensive system of spaces, lined with columnar 

 epithelium, that lead to all parts of the organ (Fig. 12). As has 

 been shown for other species of pteropods food passing from the in- 

 testine enters these spaces and is acted upon by the digestive fluids. 

 Peck, speaking of C. calceola^ says, "there are also tracts of ciliated 

 liver cells, situated at various points along the central spaces; they 

 line the passage from the intestine out into the liver and serve doubt- 

 less for transporting food particles etc., whenever they occur". There 

 is no reason for doubting the correctness of Peck's observations which 

 are invariably very accurate but in Corolla spectahilis this condition 

 of affairs has not been found to exist. The matter is often compli- 

 cated by the abundance of coagulated nutritive material and the di- 

 gestive secretion but where the walls are bare cilia are absent. This 

 may be the result of the reagents but in other parts of the body 

 cilia are excellently preserved. 



As Peck has shown the liver ducts lead into an extensive series 

 of small crypts, lined with secreting epithelium, that gives this gland 

 its characteristic spongy character. In these cells are spherical bodies, 

 often very minute, at other times swelling the secreting cell to an 

 almost globular form while in yet other cases the escaped droplets 

 are accumulated in the liver ducts. In this latter situation these 

 glandular products rapidly dissolve and probably act upon the neigh- 

 boring food products. 



A branch of the visceral aorta sends an abundant blood supply 

 into the spacious sinuses with which the liver is supplied. 



