252 NEW YORK STATE MUSEUM 



The crop is elongate oval (pi. 5, fig. 3, 4), having a diameter 

 three or four times that of the esophagus. Exteriorly it has a 

 somewhat plicated appearance, caused by the longitudinal folds 

 of the interior. It is situated in the first volution alongside of a 

 part of the spermatic duct. 



On each side of the crop are situated the salivary glands (pi. 5, 

 fig. 3, 4). They are elongate, somewhat oval, and arborescent in 

 appearance. They extend nearly the entire length of the crop. 

 They are white in color, and under the magnifying glass present a 

 beautiful appearance. They are composed of lobules, which are 

 the dilated beginnings of the ducts, lined with cells oval in form 

 and having a nucleolated nucleus. The glands are connected 

 with the mouth by ducts, which extend alongside the esophagus. 

 They are cylindric and conspicuous (pi. 5, fig. 3).^ 



The stomach begins almost immediately at the termination of 

 the crop (pi. 5, fig. 3). At first it is small, but little greater in 

 diameter than the esophagus, but rapidly and regularly increases 

 in size nearly to its extremity. A transverse section is circular 

 in outline. The anterior part is situated in the first volution of 

 the shell, lying alongside the spermatic duct, continuing, having 

 on one side the larger lobe of the digestive gland, and the 

 albumen gland, on the other side being in contact with the herm- 

 aphroditic duct. It continues to the superior or smaller end of 

 the digestive gland and ovotestis, where it bends somewhat 

 abruptly downward and backward, giving origin to the intestine. 

 Its walls are apparently striated and very thin. The contents of 

 the stomach can be seen through the walls. For illustrations of 

 the crop and intestines see plates 5, 6, 10 and 14. 



The intestine is of about the same diameter as the esophagus. 

 Immediately on leaving the stomach, it turns backward below 

 the stomach to the large lobe of the digestive gland, following the 



1 According to A. B. Griffiths (F/iys. invert, p. 109), the following constituents are 

 found in the salivary secretions : soluble diastatic ferment, capable of converting starch 

 into glucose, calcium, chlorin and doubtfully sulfocyanates and calcium phosphates. In 

 the branchiate Gasteropoda the latter two substances occur, as well as mucin, but 

 doubtfully chlorin. 



