PHYLUM PLATYHELMINTHES 



Leeches. Save in two exceptional cases (TemnowpKcda) vibratile 

 cilia are not known to occur on the surface in the adult condition ; 

 in some there are groups of non-motile cilia, situated on little 

 conical elevations the tactile con*'*. Pigment is rare in the 

 endoparasitic Digenetica, save in a few that live in the interior of 

 transparent animals, though many appear coloured variously by 





FIG. 191. Actinodactylella. 6. c. bursa copulatvix ; 6)-. .bniin ; r. penis ; I. intestine; or. 

 ovary; ph. pharynx; /. r. receptaculum vitelli ; t., t. tcstes ; r. vitelline glands; r. .s. 

 vesicula seniinalis. (After Haswell.) 



the internal organs shining through the translucent body wall, or 

 are stained by some fluid derived from their host. But pigment 

 is found in some of the ectoparasitic forms. 



The relationship of the Ccstoda to the Trematoda is, as will" be 

 subsequently shown, fairly close ; but, though there are connecting 

 forms between the two classes, the shape of the average Cestode 



