Finally, the last family D actylogyridae is encountered on 12 

 orders of fishes; however, in order to show more clearly the peculiarities 

 of the distribution of worms pertaining to this family we shall analyze the 

 distribution of the three subfannilies --Dactylogyrinae, Ancyiocephalinae, 

 and Linguadactylinae-- separately. 



Dactylogyrinae are authentically known from four orders -- 

 Cypriniformes (the basic mass of species of all known genera), Perci- 

 formes, Anguilliformes, and Gasterosteiformes. Among Cypriniformes 

 these worms are encountered on Cyprinidae (the basic mass of known 

 species), Catostomidae and Cobitidae. These three families are related 



to the suborder Cyprinoidei and undoubtedly are closely linked genetically 

 (Suvorov, 1948), The representatives of the genus Dactylogyrus are en- 

 countered on the remaining orders of fishes (page 262) and one species of 

 Acolpenteron from Centrarchidae (page 256). One must note here only that 

 the two species indicated in the table for Anguillidae- -Dactylogyrus bini 

 Kikuchi and D. anguillae Yin and Sproston (discovered on Anguilla japonica), 

 are apparently the same because the differences indicated by the authors 

 are not significant (Yin and Sproston, 1948). In conclusion, one may con- 

 sider that Dactylogyrinae are characteristic for Cypriniformes and, as 

 exceptions>are encountered on ether orders of fishes, but the latter do not 

 have any genetic links with each other or with Cypriniformes. 



Ancyrocephalinae (in their contemporary scope^ which seems 

 artificial to us, see page 348) are shov.Ti as parasitizing 10 orders of fishes 

 (Table 16). Of these orders, the Perciformes bear the majority of species 

 and genera, among which these wornns are encountered in the suborders: 

 Percoidei (16 families--101 species of worrr^s), Siganoidei (1 family--4 

 species), Acanthuroidei (1 family--4-3 species), Gobioidei (2 families-- 

 3-1 species), Cottoidei (1 family--4 species). Second in order, judging 

 by the quantity of species of parasites, are Cypriniformes, among them 

 Ancyrocephalinae are encountered on three families of the suborder 

 Cyprinoidei (14 species of worms), and 6 families of Siluroidei (28 species). 

 Ancyrocephalinae are encountered in a small number of species (from 1 to 

 9) on all the remaining eight orders of fishes. One must note that, among 

 the five (?, nobis) of them there is not a single independent genus of Ancyro- 

 cephalinae. Thus, this subfanaily of Dactylogyridae is basically distributed 

 among Perciformes and Cypriniformes, not connected with each other by 

 close relations, and in isolated cases are discovered on representatives of 

 other orders whether related or not related with the first two or among 

 themselves. 



Linguadactylinae, as is known, are encountered only on Gadiformes 

 (see page 352 ). 



Finally, speaking as a whole about Dactylogyridae we must note 

 that as a rule tnis family is encountered on two orders --Cypriniformes and 



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