finding of circular, rbund, small bodies in the cuticular structure of the 

 young worms. Finally, a number of researchers headed by Pratt (Pratt, 

 1909) and Schneider (Schneider, 1873) suppose that adult forms of para- 

 sitic flatworms have lost their epithelium completely, which thus is pre- 

 sent only among larval stages and is cast off during metamorphosis. 



ODtMM 



Fig. 55. Coverings of monogenetic trematodes. A- - Ancylodiscoides 



magnus Bychowsky and Nagibina; B - - Aca nthocotyle williamsi 

 Price; C--Tristoma coccineum Cuvier. 



According to this point of view, the cuticle of parasitic flatwornns is a 

 derivative of the parenchyma and is equivalent to the basal membrane of 

 Turbellaria. This point of view was advanced in recent times by Poche 

 (Poche, 1929) who proposed to replace the appellation "cuticle" for para- 

 sitic flatworms by a new one "pseudodermis" and for subcuticular cells the 

 appellation "pseudodermals" (pseudoderinal cells). 



p. 41 



35 



