Plate XIII. 



Hexacotyle acuta. 



Fig. 1. The wliole worm viewed from tlie veutral side. From a specimen killed 



under a slight pressure. ' 



„ 2. Hooks at the posterior extremity of the body, x 204 diam. 

 „ 3. Chitinous pieces of the posterior sucker. x204 diam. a, that at the 



anterior end ; A, that at the middle ; c, that at the posterior end. 



Hexacotyle grossa. 



Fig. 4. The whole worm viewed from the veutral side. Nerve yellow ; excretory 

 vessel indigo-blue. 

 „ 5. Hooks at the posterior extremity of the body, x 204 diam. 

 „ 6. Chitinous pieces of the posterior sucker, a, b, c as in fig. 3. 



