species which means that this is not an exclusive peculiarity of P. 

 integerrimum but is common to the entire genus or at any rate to a 

 number of its representatives. 



P. ozaki Price 

 apparently has a similar 

 development to P. integerrimum 

 but with a more delayed tempo. 

 This type resennbles the first 

 extremely closely but differs by 



0.07MH 



Fig. 207. Polystomoides 

 oris Paul, free-swimming 

 larva. (According to Paul, 

 1938). 



1\m 



Fig. 208. Poly stomoide s oris, Paul, 

 two stages of developmient of the young 

 worms from the buccal cavity of the 

 turtle Chrysemys picta (Schneider). 

 (According to Paul, 1938). 



a powerful development of the digestive system. We have observed the 

 process of nnetamorphosis of the larva of this species in the young frog 

 (Rana chensinensis Dov. ) on southern Sakhalin in the regions of Antonov 

 in 1946~ The larvae -reached the urinary bladder of the frog at earlier 

 stages than among P. integerrimum , i. e. , while they do not even have 

 the first pair of suckers. 



17. The development of Polystomoides Ward 



The genus Polystomoides is characterized by the presence of 

 one large testis, by the absence of a uterus (there is only an ootype), and 

 by simple, unbranched intestinal trunks (Fig. 82). Paul (Paul, 1938) 

 worked on the development of P. oris Paul fronn the buccal cavity of 

 Chrysemys picta (Schneider). The larva develops in the eggs for approxi- 

 m.ately 28 days. Upon emergence from the egg it swims freely, thanks 

 to the four zones of ciliary epithelium (Fig. 207). The structure of the 

 larva is very simdlar to that of the representatives of the genus Polystoma . 

 Its sizes are 0. 275 by 0. 065 mm. The attaching disc bears 16 pairs of 



p. 187 



202 



