118 MOLLUSC A. 



1. The pair of large, white nidamental glands that cover a 

 portion of tlie rectum and the greater part of the ink-bag. 



2. The openings of these glands at their anterior ends. Do 

 you know the function of these glands? 



3. The opening of the oviduct dorsal to, and a little to the 

 left of, the left nidamental gland. 



4. The mass of eggs that fills the posterior portion of the body. 

 These are in the ovary and oviduct. 



Draw the animal, showing the points observed. 



Excretory System. — If the animal is a female, remove the 

 nidamental glands, and the kidneys will be seen in the position 

 described for the male. The kidneys consist of: 



1. The white, somewhat triangular, glandular portions already 

 noticed, extending from the region of each branchial heart ante- 

 riorly, and forming a portion of the walls of the pre-cavae. 



2. The 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 mus- 

 cles and carefully lay the head open, along the ventral side, to 

 expose the buccal mass. This is a rounded, muscular organ, 

 with a ring of tissue at its anterior end that surrounds the horny 

 jaws. Examine the jaws and see which is the larger. Trace the 

 narrow esophagus from the posterior end of the buccal mass back- 

 ward. 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 exter- 

 nal openings of the kidneys. Lying 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 stom- 

 ach. Before entering the stomach the esophagus passes the 

 pancreas, a white, lobed organ that lies just beneath the glandular 



