of the basic middle plate with one of the anterior lateral and this merging 



takes place in such a way that the large part of the space between these 



plates is occupied by a thin membrane which departs from the middle and 



at the same time adheres to the edge of the lateral plates 



in such a fashion that only a small oval opening remains in the lower part 



of the single plate which was formed between them (Fig. 306, II). Apparently, 



0.1mm 



Fig. 304. Choricotyle pagelli 

 (Gallien), attaching clamp of an 

 Sparus centrodontus (Delar. ) 

 near the western shore of England 

 (Atlantic Ocean). Explanation in 

 text. 



Fig. 305. Heterobothrium affinis 

 (Linton), the attaching clamp of an 

 adult worm from the gills of 

 Atherestes evermanni J. and St. 

 from the region of the Cape of 

 Navarin (Bering Sea). Explanation 

 in text. 



the described membrane corresponds to the strongly developed triangular 

 membrane of Heterobothrium. The remaining chitinous plates are more 

 or less symmetrical. The muscular cluster enters into the clamps through 

 the oval opening which was indicated and apparently attaches to the interior 

 surface of the membrane. Usually the clamp is in the half -closed state, 

 forming an oval, si it- shaped aperture. 



One must say that the majority of the drawings of the skeletal 

 formations of the clamps reproduced by various authors in their works 

 leave much to be desired. Nevertheless in Cerfontaine and Yamaguti and 

 also in a number of others the descriptions of the clamps of different 

 species of Diclidophoridae are quite correct. During the study of the 

 literary data we see that the peculiarities of the structure of the clamps 

 of the separate genera described by us are observed in all their species 

 or at any rate in all well-described ones. Exceptions apparently depend 

 on the inaccuracies of the studies of the corresponding species. Thus, 

 Gallien (Gallien, 1937) represents the chitinous elements of the clamp of 



p. 436 



521 



