In this connection, one cannot refuse to accept the opinion 

 of a number of researchers who consider that in addition to similarities 

 based on genetic consanguinity, a great role is also played in the process 

 of evolution by parallelisms and convergencies (Berg, 1922; Beklemishev, 

 1952 and others) the elucidation of which will give us the possibility of 

 a more accurate analysis of historical interrelations. 



Inasmuch as for further discussions of the question about 

 the phylogenetic ways of development of naonogenetic trematodes it is 

 indispensable to bring in special materials we shall stop with what has 

 been said for the time being and will pass on to the questions aboitthe 

 systematics of contemporary forms in order to return again to the 

 questions on the construction of the phylogenetic schemes of the group 

 after this. 



391 



