42 



jirulLiberanees on Mu' five surfaces of the cells t(t long tentacle-like processes. 

 This variation leads to the supposition that tlie processes are capable of being 

 extended and witlidrawn. In young squid the pi'ocesses retain their independence 

 but in rlie adult the processes of several adjacent cells fuse and form an irregular 

 coral-like mass. These masses often contain bodies which appear to be tVidd 

 granules and vacuoles. 



In transparent yoimg, 5 or (> mm. long, the rectal valves can be seen 

 beating downward into the anus and as they descend the anal lips open ; as they 

 rise , the anal lips close. This action drives water into the rectum and in an 

 experiment particles of carmine in the water were carried into the rectum. 

 Contractions of the rectum drove the water out through the anus while the 

 carmine was retained , probably being screened out by the processes , and was 

 then carried by cilia as far as the proximal end of the intestine. The appearance 

 of the rectal cells in the adult leads us to suppose that the processes are truly 

 pseudopodial and that the granules in them are food particles undergoing intra- 

 cellular digestion. Intestinal pseudopodia and intra-cellular digestion have not, we 

 believe . been described in any mollusc and it will be surprising if it is proven 

 that structures and habits commonly associated with much simpler animals occur 

 in the highest of the mollusca. 



The ink sac. The ink sac is a large pear-shaped organ situated above the 

 rectum , below the anterior vena cava and the liver , and in front of the nephridium 

 whose median portion separates it from the intestine. The ink sac arises from 

 an evagination of the upper side of the distal end of the rectum and becomes 

 differentiated into three portions : a dorsal glandular portion , a large conical 

 reservoir, and a short duct which leads forward from the small end of the 

 reservoir to the anal chamber. The glandular portion is oval and consists of a 

 series of connected chambers lined by a cubical glandular epithelium which 

 secretes the jet black ink. The size of the chambers increases rapidly from the 

 small dorsal chamber to the large ventral chamber which occupies the greater 

 part of the ventral half of the glandular portion and opens into the reservoir 

 thru a small opening in the middle of its convex ventral surface. The dorsal 

 half of the glandular portion is attached to the wall of the sac but the ventral 

 half i)rojects freely into the reservoir in which the ink is stored. The reservoir 

 is a conical chamber whose large dorsal end is formed by the glandular portion 

 of the ink sac and whose narrow ventral end is continuous with the duct from 

 which it is separated by a sphincter. This chamber is homologous with the 

 reservoir and the long tubular portion of the duct of Sepia while the duct of 

 Loligo is homologous with the small terminal chamber or "ampuUe" of Sepia 



