Plate XIII. 



H E X A C T Y L E ACUTA. 



Fig. 1. The whole worm viewed from the voiitral side. From a specimen killed 

 under a slight pressure. 



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



3. Glutinous pieces of the posterior sucker. x 204 diam. a, that at the 

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



HeXACOTYLE GBO s sa. 



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

 vessel indigo-blue. 

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

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



