A Study of One of the Distomes. 91 



the general covering of the body. A multitude of these 

 bundles united surround the sucker, and when the animal is 

 active they extend out, at nearly a right angle with the long 

 axis of the body, and thus come very much nearer the center 

 of the sucker than here shown. In fact, in some cases they 

 appear to meet completely, and the whole sucker seems made 

 up completely of these bundles. The cut shows these fibers 

 relaxed and flattened, a result of death" and manipulation. 

 The fibers of this sucker are so arranged that when applied 

 to any soft surface they must, during their full action, tend to 

 create a vacuum in the center, thus serving as a hold-fast or 

 anchor to the body. 



The cephalic sucker (Fig. 3) is similar to its fellows in 

 construction, only it is perforated, and has the addition of the 

 lance (^B). We recognize the well developed fibers forming 

 the walls of the pharynx at C. When our distome desires to 

 move from place to place, the acetabulum becomes fixed, and 

 by the contraction of the circular fibers between it and the 

 anterior sucker, the distance between them is increased, this 

 part of the body being reduced to one-half its former trans- 

 verse diameter and increased accordingly in length ; thus the 

 cephalic sucker is pushed ahead. Now it, in turn, becomes 

 fixed by a mechanism precisely like that of its fellow. The 

 acetabulum and the fibers relax their hold and the body is 

 drawn up a distance of nearly one-fifth the length of the 

 animal. While the acetabulum is fixed that part of the body 

 in front of it will swing from side to side, showing the 

 greatest degree of contractility. 



One will very rarely fail to see the distome casting its 

 eggs. It is a most beautiful and instructive sight. It can 

 be seen sufficiently well with a ^-inch objective, with the 

 process of segmentation going- on. 



Fig. I, ' represents these eggs as they appear when first cast 

 off. By the general contractions of the body, aided by the 

 cilia at the upper part of the uterine tube, these eggs are 

 thrown off, usually three or four at a time, to be followed in 

 a few seconds by as many more. At a single examination 

 over two hundred were cast off, yet to all appearances as 

 many were in the body as before. Some of these eggs 

 should be removed to a very shallow cell, normal saline so- 

 lution added, and high powers employed, and the process of 



