1 16 SELACHINEMA 



contained nematode remains, indicates characteristics of these carniv- 

 orous species. 



The cells of the intestine, separated from each other by thin refrac- 

 tive walls, had the form of rather regular polyhedrons, and each con- 

 tained a distinct subspherical nucleus having a diameter about one- 

 third as great as that of the cell itself. This nucleus was supplied 

 with a distinct nucleolus. Between its nucleus and the wall each cell 

 contained a large number of brownish-yellow spherical granules of 

 somewhat variable size, the largest having a diameter , one-fourth to 

 one-fifth as great as that of the nucleus, and the smaller varying from 

 this size downward. These granules had a tendency to gather next 

 to the intestinal lumen. The nucleus, therefore, lay nearer the outer 

 surface of the intestine than the inner. In the anterior part of the 

 intestine all the cells except the cardiac cells had the same character. 

 Through the middle of the body the intestinal cells varied from those 

 in the anterior part of the body in that the granules were somewhat 

 smaller, and less numerous, so that the clear spaces in the cells had 

 relatively greater volume. Behind the middle of the body certain of 

 the cells constituting the wall of the intestine were markedly different 

 from those just described, although these latter continued to consti- 

 tute the main portion of the intestinal wall. These markedly differ- 

 entiated cells were twice as large as the others and contained larger- 

 granules of more uniform size. One of these larger cells may be most 

 advantageously examined when it occurs opposite the lateral field, 

 where the refractions due to the muscular cells of the body wall do 

 not interfere with the view. It may then be seen to have an elliptical 

 contour, at least when seen face view, and to contain a nucleus half as 

 wide as itself. The nucleus in turn contains a nucleolus having a 

 diameter one-third as great as its own. The total number of granules 

 in one of these giant cells was between 50 and 100, and owing to the 

 relatively large size of the nucleus they were located more particularly 

 toward the ends of the cell. The granules were of rather uniform 

 size and had a diameter about twice as great as that of the largest 

 granules in the ordinary intestinal cells. There were 20 to 30 of these 

 scattered giant cells in the posterior fourth of the intestine. 



May, 1915 



