Protomicrocotylidae are discovered on Carangidae (4 species 

 and 2 genera of worms) and Sciaenidae (1 species). Generally the relations 

 between these two families of Percifornnes are not very close (Gregory, 

 1951). 



Plectanocotylidae are known fronn Serranidae, Triglidae 

 (2 species), Trichiuridae and Carangidae, i.e., from fishes related to 

 three different suborders of the Perciformes; however, one cannot fail 

 to note that Gregory ascribes Trichiuridae and Carangidae to one branch 

 of development of Perciformes (Gregory, 1951), and Serranidae and 

 Triglidae have certain consanguinous links. 



Tetraonchidae are encountered on Salmonidae, Thymallidae 

 and Esocidae. This family, which contains only one genus, has already 

 been indicated (page 256 ). We shall reiterate that L. C. Berg considered 

 it beyond doubt that the suborder of Salmonoidei, to which the first two 

 families belong, and Esocoidei stand side by side in the system of fishes, 

 and are genetically linked with each other. 



Seven families --Anthocotylidae, Calceostomatidae, Dionchidae, 

 Discocotylidae, Gastrocotylidae, Mazocraeidae and Monocotylidae are 

 encountered on two orders of fishes', however, the relations with the hosts 

 in each fannily are different. 



Anthocotylidae are encountered in two families of Perciformes: 

 Carangidae (1 genus, 2 species of worms), and Gemphilidae (1 species); 

 and on one family (Merluciidae) of Gadifornnes (1 species). Even though 

 they are far removed from each other, according to the systenn of L. C. 

 Berg, the first two families can be considered as closely related because 

 Gemphilidae are close to Trichiuridae (they form a single suborder 

 Trichuroidei), whereas the relations of the latter with Carangidae are 

 apparentlv close (see page 273). Only one widely distributed species, 

 Anthocotyle merluccii Beneden and He£se--a parasite of Merluccius 

 merluccius (L. )-- is known from the Gadiformes. Gadiformes apparently 

 are in sonae genetic relation with the Perciformes, as is considered by the 

 majority of contenaporary ichthyologists (Svetovidov, 1948). 



Calceostomatidae are known from one family of the Perciformes 

 and two families of Cypriniformes. The data about one of the latter demand 

 verification (see page 363 ). The relations of both orders are not clear, but in 

 any case they are sufficiently distant from each other (Suvorov, 1948; 

 Nikolsky, 1954). 



The correlations between the hosts of Dionchidae were exanndned 

 before because this family contains only one genus (see page 256). 



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