The second group of anterior attaching structures, as has been 

 stated above, is associated with the oral aperture and the buccal funnel. 



Fig. 14. Diplectanuni similis Bychowsky, 

 adult worm from the gills of Corvina nigra 

 Cuv. and Val. from the region of Karadaga 

 (Black Sea). 



Fig. 15. Empruthotrema 

 raiae (MacCallum), adult 

 worm. (According to Price 

 1938) 



Actually, we deal with two separate structures, to be more pre- 

 cise with the changes in shape of the anterior end of the buccal funnel and 

 with its suckers. 



In the simplest case the external edge of the buccal funnel serves 

 for adhesion (for example Linguadactyle , Fig. 21). Further, we have all 

 stages of transition to the formation of a more or less well-developed oral p. 

 sucker around the oral orifice at the expense of the buccal funnel Squaloncho- 

 cotyle. Fig. 2; Polystoma, Fig. 22). Apparently in unusual cases one of the 

 edges of the mouth sucker can form a series a series of sucking pits, but 

 in no case do they represent the transitional link to the following group. In 

 other cases in which there are no changes in the external edge of the buccal 

 funnel, which remains in its primitive state, on the internal surface of the 

 funnel along its sides there begin to form two internal suckers which in 

 various species reach differing degrees of attaching capabilities (Figs. 23,24). 

 These suckers of the buccal funnel are not connected in origin with the other 



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