Plate XII. 



DiCLIDOPHOEA ELONGATA. 



Fig. 1. CLitinous fi-anne-work of the posterior sucker in surface view, x about 73 

 diam. The semicircular series of chitinous, rod-shaped pieces are repre- 

 sented only in one quadrant. 

 „ 2. One of the semicircular series of chitinous, rod-shaped pieces represented in 

 the preceding figure, x 204 diam. 



DiCLIDOPHOEA SESSILIS. 



Fig. 3. Optic cross-section of the prismatic fibres of the posterior sucker ; x 305 

 diam. 

 „ 4. Section of a posterior sucker parallel to the length of its pedicel, x 204 

 diam. 



Hexacotyle acuta. 



Fig. 5. Median part of a cross-section of the body, to show the prostate glands 



Ventral side below, x 204 diam. 

 „ 6. Median sagittal section through the region of the genital opening. x 73 



diam. The vas deferens opens into the genital atrium in the next section. 

 „ 7. Section of the hinder extremity of the body at a right angle to the posterior 



border, to show the structure of the sucker, x 73 diam. 



Hexacotyle geossa. 



Fig. 8. One of the intestinal trunks near its hinder end, in a surface view, x 73 

 diam. 



