Jord. and Sn.^ and the individuals from the Far Eastern fishes were placed 

 by us into a special subspecies G. g. pacificus Bychowsky and Poljanski 

 (Bychowsky and Poljanski, 1953). All the hosts are related to Cottidae, 

 but are nevertheless distant from each other. The impression is created 

 that in addition to the consanguinity, contemporary ecological factors also 

 play a role here--G. groenlandicus infests fish living on the littoral w^here- 

 as the individuals of the same fishes which inhabit depths remain free from 

 this parasite. As a matter of fact, we have already spoken about certain 

 ecological influences on infection in the chapter about life cycles and, in 

 addition, this question will be studied specially later (page 286). 



G. gobioninum was recently described by A. V. Gussew from 

 fishes related to six genera, Hemibarbus, Pseudoraspora , Chilogobio, 

 Sarcochillchthys, Pseudogobio, and Saurogobio. According to Kruzhanovsky 

 (1947) all these genera are related to Gobioninae (Gobiini, nobis) whereas 

 according to Berg the first genus belongs to Barbini and the rest to 

 Gobiini (Berg, 1912). At any rate the hosts of G. gobioninus are rather 

 removed from each other and judging from the morphological data, this 

 species apparently is cumulative (lumped from a number of species that 

 should be separated, nobis) as Gussew noted and described it (1955). Thus 

 it is more probable that the "forms" from different hosts appear to be 

 independent; in any case, this applies to the one parasitizing Hemibarbus. 



The last species of this group which we consider necessary to 

 discuss is Mazocraes harengi (Beneden and Hesse) indicated for Clupea 

 harengus L. and Alosa alosa L. , fishes related to different subfamilies 

 (Svetovidov, 1952). Because CI. harengus is the typical host of M. harengi 

 the correctness of the data about the finding of this parasite on A. alosa is 

 subject to doubt. As far as we know the indication on the last host exists 

 only in the work of Baylis and Jones (Baylis and Jones, 1933). During the 

 evaluation of this work, it appears that actually M. harengi is indicated for 

 Clupea (=Alosa) alosa first according to the data of "the junior author" 

 (Jones). Until there are sufficiently documented subsequent findings^ we 

 have no basis for taking these data into account. It is more probable that 

 the "junior author" is simply mistaken in the determination and was dealing p. 243 

 with Mazocraes alosae which, it must be mentioned, he was finding on 

 Alosa finta. The numerous studies on the herrings which were conducted from 

 1933 which indicate the absence of M. harengi on representatives of the genus 

 Alosa can serve as substantiation for this. 



All in all, one can consider that the degree of proximity of the hosts of 

 Monogenoidea which are encountered among fishes of different genera of one family is 

 not characterized only by belonging to the latter but it is considerably larger and the 

 worms are usually encountered on the genera closer to each other than to genera of a 

 given family as a whole. 



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