with the middle hooks completely differently. Thus the ventral pair of 

 hooks connects with the ventral plate which is homologous to the middle 

 plate of Diplectanidae and M. robustum , whereas the dorsal plate, which 

 is divided (in phylogenesis and perhaps in ontogenesis) into two parts >is 

 linked by each separate part with the corresponding dorsal middle hook. 

 Thus, here completely different correlations occur. Without entering 

 into excessive details, we should also indicate in connection with what 



_ 



One can suppose that in contrast to Murraytrema, Pseudomurraytrema has 

 intestinal trunks which merge somewhat away from the posterior end. 



has been said, that there are all the (necessary, nobis) foundations to 

 separate the new genus - - Pseudomurraytrenna Bychowsky gen. nov. con- 

 taining the single species P. copulatum (Mueller) Bychowsky comb, nov . 

 ^rom the old genus Murraytrema, nobis) parasitizing fishes of the fannily 

 Catostomidae. In connection with this, Murraytrema appears to be a 

 monotypical genus encountered only on one family of fishes. 



The genus Tagia until recently was monotypical, but in 1949 

 the second species T. micropogoni Pearse was described. This was done 

 completely unsatisfactorily and the drawings are such that they force us to 

 doubt the correctness of the attribution of this species to the given genus 

 and that the author had a complete specimen of the worm (Pearse, 1949); 

 therefore, one should consider that Tagia must be excluded during further 

 discussion . 



Although the genus Thoracocotyle is cited as parasitizing two 

 families of fishes it is nevertheless incorrect, just as the indication of its 

 presence on Coryphaenidae is a result of the incorrect attribution to this 

 genus of the type, T. coryphaenae Yamaguti, by Yannaguti hinnself. A 

 special structure of the attaching clannp is characteristic (Meserve, 1938, 

 Table 7, Fig. 43), as well as a different type of armature of the sex 

 system for the present representatives of Thoracocotyle. In contrast to 

 them, the form described by Yamaguti has an internal structure typical for 

 Microcotyle ^ and its clamps resemble rather those of Gastrocotyle , Pseud - 

 axine and others and do not resemble the ones possessed by Thoracocotyle 

 at all. In such a fashion T. coryphaenae should be transferred into the 

 genus Microcotyle (s. lat. ), whereas the genus Thoracocotyle should be 

 transferred into the group encountered only on one family of hosts. 



The genus Metahaliotrema was encountered by its author on 

 two very distant families (different orders !). Unfortunately we did not 

 have the work of Yamaguti (Yamaguti, 1953) and consequently cannot say 

 anything definite. 



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