organ of Acanthocotylidae and in particular Lophocotyle is clearly of the 

 dactylogyrid-type and not gyrodactylid. Thus, in both cases the ancestors 

 of Acanthocotylidae should be sought only among the same order to which 

 we ascribe this family. However, it is difficult to solve the above- 

 mentioned question without special research. We are inclined to think 

 that the hooks of the disc lying in the middle are truly middle hooks derived p. 384 

 by analogy from Calceostomatidae, among which the edge and the middle 

 hooks are very similar in structure during the early stages of development. 

 Nevertheless, the point of view of Sproston (Sproston, 1946) who separates 

 Acanthocotylidae into a special superfamily Acanthocotyloidea Sproston, 

 1946, deserves considerable attention. A basis for this, according to 

 Sproston, is the presence of a secondary disc among adult forms which, as 

 she writes, are absent among all other Monogenoidea. However, Sproston 

 retains only 2 genera --Acanthocotyle and Lophocotyle- -within the limits 



of the family Acanthocotylidae, excluding from it the genus Enoplocotyle 

 which does not retain a secondary disc. This is not correct and does not 

 reflect the true relations of the genera enumerated which have obviously 

 close relationships with each other. This alone indicates that it is hardly 

 permisible to accept the system of Sproston or another analogous system 

 without supplementary research, particularly on the development of all 

 three genera enumerated above. Consequently, we temporarily leave 

 Acanthocotylidae within the limits of Monopisthocotylinea although this may 

 not be altogether correct. 



Price (Price, 1936, 1938a) divides Acanthocotylidae into two 

 subfamilies --Acanthocotylinae Monticelli, 1903 and Enoplocotylinae Tagliani, 

 1912 which seems fully justifiable to us. 



1. Subfamily Acanthocotylinae Monticelli, 1903 



(Figs. 18, A, 55, B, 112, 113, D, 313) 



Acanthocotylidae, having, in addition to the primary, a well- 

 developed secondary disc which is armed or unarmed with thorns. The 

 trunks of the intestine are with or without lateral outgrowths. The testes 

 are numerous. 



Parasites of the skin of skates and Nototheniidae (?). 



Type genus, Acanthocotyle Monticelli, 1888. 



In addition to the type genus another- -Lophocotyle Braun, 1896- 

 also belongs to the subfamily. 



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