As a whole Hexastomatidae undoubtedly are secondarily changed 

 species, and it is most probable that they are close to Mazocraeidae. This 

 is indirectly substantiated also by the parasitizing of fishes which are close 

 phylogenetically as well as ecologically. 



2. Suborder Discocotylinea Bychowsky, subord. nov. 



Mazocraeidea,of middle and large sizes. The attaching armature 

 of adult individuals consists of 4 or more pairs of clamps and one pair of edge 

 and 1-2 pairs of middle hooks. In a number of cases the hooks can be fully 

 or partially absent. The clamps have a chitinous supporting apparatus, but 

 the latter never forms a capsule, but consists of separate little parts 

 articulatinp" 3-t their ends. The intestine is with 2 trunks and as an 

 exception is net-shaped. 



Parasites of marine and freshwater fishes, basically Perci- 

 formes and Clupeiformes. 



The suborder consists of 7 families: Discocotylidae Price, 

 Anthocotylidae Bychowsky, fam. nov. ; Plectanocotylidae Bychowsky, fam. 

 nov. ; Diclidophoridae Fuhrmann; Microcotylidae Taschenberg; Proto- 

 microcotylidae Poche; Gastrocotylidae Price. 



The system of the present suborder has not yet been completely 

 analyzed. It is possible to suppose that its juxtaposition to Mazocraeinae 

 is in order and will hardly ever be subjected to doubt. As regards the scope 

 of Discocotylinea, it is possible that in the future this suborder will have to 

 be subdivided by extracting Plectanocotylidae and the related Gastrocotylidae 

 from it. 



1. Family Discocotylidae Price, 1936 



Octocotylidae auct. part. 



Discocotylinea, having middle sizes. The attaching apparatus 

 consists of a disc more or less well— delimited from the body, which carries 

 one pair of middle hooks and 4 pairs of attaching clamps in the adult forms. 

 Each clamp is equipped with 5 chitinous plates. The eyes are absent among 

 adult forms (the larvae have 2 eyes or one double). The intestines are double 

 or in the shape of a single trunk forming a number of outgrowths. The 

 copulatory organ has a chitinous armature in the shape of a small pipe. 

 It is either not armed or is completely absent. The testes are numerous 

 or there is only one of them. The vaginal ducts are either present or absent. 

 The animals are single or growing in pairs. The other characteristics are 

 similar to those of Mazocraeidae. 



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