S2 JOHN E. GUTBERLET 



and form a compact layer. The inner boundary of the suckers 

 is composed of a layer of fibers which are both circular and oblique. 

 Some of these at the upper edges are associated with similar fibers 

 in connection with the rostellar sac. 



The cyst is composed of two cell layers with an irregular 

 cavity between them. The cells are large and irregular in shape 

 with no special arrangement in the layer. Large intercellular 

 spaces lie between the cells, thus forming a loose network structure, 

 except at the base of the neck. At this point where the neck is 

 attached to the inner layer of the cyst the cells are smaller and 

 are in a compact mass. There is no definite boundary to the outer 

 part of the inner layer as well as to the inner part of the outer 

 layer of the cyst. Few cells with long connective processes extend 

 across the cavity from one layer to the other. This then forms 

 an irregular cavity (Fig. 11 ca) 2 to 20ijl in width between the two 

 layers of the cyst. This is the primitive cavity of Grassi and 

 Rovelli (1889: 373). The two layers of the cyst are formed 

 apparently by a fold which extends upward and inward from the 

 base of the neck, forming the gastrula cavity of Grassi and Rovelli 

 (1889: 402, g) and enclosing the scolex. This cavity varies in 

 width from 3 to 10 or 15/i. 



The bladder, an oval shaped structure, is located at one side 

 of the cyst and is attached to it at the posterior end by a narrow 

 connection (Fig. 12, en). The posterior end of the cyst or the 

 region caudad of the base of the neck is somewhat drawn out 

 (Fig. 12). From this point is given off the attachment to the 

 bladder or tail portion of the cysticercoid. The fact that this 

 bladder is really a tail, even though it possesses a cavity, is shown 

 by the presence of the onchospheric hooks, which are located at 

 the end of the bladder opposite to that of the attachment of the 

 cyst (Fig. 12, oh). 



The order of arrangement of the onchospheric hooks is indi- 

 vidual. In some specimens they are situated at the end of the 

 bladder, while in others thev are at the side. In some the arrang-e- 

 ment is in a group, while in others they are in pairs. Some of 

 my specimens show a pair of embryonic hooks in the layers of 



