156 MOLLUSCA 



nidamental glands, and the kidneys will be seen in the posi- 

 tion described for the male. The kidneys consist of: 



1. The white, somewhat triangular, glandular portions al- 

 ready noticed, extending from the region of each branchial 

 heart anteriorly, and forming a portion of the walls of the 

 precavae. 



2. The f cavities of the organs lying ventrally, and at the 

 sides of the glandular portions. 



3. The external openings, at the ends of small papillae, on 

 either side of the rectum near the anterior ends of the kidneys. 



Digestive System. — Remove the funnel and its retractor 

 muscles and carefully lay the head open, along the ventral 

 side. 



Find: 



1. The buccal mass. This is a rounded, muscular organ, 

 with a double ring of tissue, the buccal membranes, at its 

 anterior end, that surrounds the horny jaws. Examine the 

 jaws and see which is the larger. 



2. Behind the buccal mass are the paired salivary glands. 



3. Trace the narrow esophagus from the posterior end of 

 the buccal mass backward. At the base of the head it enters 

 the liver, a large, white organ that lies between the retractor 

 muscles of the head, and extends from the base of the head to 

 a point dorsal to the external openings of the kidneys. Ly- 

 ing close to the esophagus and covered by the anterior end of 

 the liver is an elongated median salivary gland, the duct from 

 which follows the esophagus into the head. The esophagus 

 leaves the liver about midway of its length, and follows along 

 the ventral surface nearly to the stomach. Before entering 

 the stomach the esophagus passes the pancreas, a white, lobed 

 organ that lies just above the glandular portion of the kid- 

 neys, and the systemic heart, a roughly diamond-shaped organ 

 that lies between the branchial hearts. 



The stomach proper is a rather small, thick-walled sac 

 that lies on the right side of the body, dorsal and posterior 

 to the right branchial heart. From the left side of the stom- 



