As regards the internal anatomy, the structure of the sex 

 system, particularly of the vitellaria and their ducts, is most interesting. 

 However, here also not everything seems reliable to us. The presence 

 of the junction of the posterior transverse vitelline duct with the intestine 

 is improbable in our opinion although it is accepted by everybody and this 

 conception has entered all the textbooks where the present family is 

 mentioned. In the text of Johnston and Tiegs concerning Protogyrodactylus 

 quadratus Johnston and Tiegs it is indicated that: "the posterior transverse 

 duct possesses a wide lumen and it is very noteworthy that it joins the 

 cavity of the intestinal trunks by means of a large aperture (Table IX, 

 Figure 3). " Similarly, for Trivetellina subrotunda Johnston and Tiegs it is p. 361 

 said that in it the posterior, dorsal transversal duct has the same junction, 

 w^hereas the ventral lacks it. The corresponding figure for the second 

 genus is not given. As regards the figure to which the authors refer, it 

 is very poorly done and on the basis of it one can suppose, not the junction 

 of the vitelline duct with the intestine but that the authors were dealing 

 w^ith the merging of the intestinal canals which, according to their des- 

 cription, do not join in the first genus. Doubt of the presence of a "vitello- 

 intestinal" junction of such type is forced upon us by considerations of the 

 functional significance of the junction between the intestinal tract and the 

 female sex system. As we showed earlier, this junction has a function in 

 the mass formation of eggs for the discharge of sex products which are 

 not utilized (see page 85). In the structure described by Johnston and 

 Tiegs, such a junction has no significance for it could serve only for the 

 discharge of yolk and only from part of the vitellaria independently of the 

 process of the formation of eggs. We are convinced that subsequent 

 studies will uphold our point of view. 



The structure of the vitelline follicles themselves and the 

 presence of the longitudinal vitelline canal is an important distinction of 

 Protogyrodactylidae from the rest of Monogenoidea. These are the only 

 two characters wliich differentiate the family from the contiguous ones 

 (see how^ever page 360 ). Hence, we can agree to the presence of the 

 family only conditionally until subsequent redescription of its representa- 

 tives which will either substantiate its independence or will force us to 

 include both genera united by it into the family Dactylogyridae. We shall 

 also indicate that on Therapon spp. are basically encountered representa- 

 tives of Ancyrocephalinae with which Protogyrodactylidae also have 

 affinities. 



One cannot fail to regret that the name of the family and genus 

 Protogyrodactvlus does not reflect the true nature of the stiuation because 

 even if all their morphological peculiarities are substantiated this will only 

 demonstrate a very high specialization and not primitiveness. 



429 



