4. Family Gastrocotylidae Price, 1943 



5. Family Mazocraeidae Price, 1936 



6. Family Hexostomatidae Price, 1936 



Unfortunately, the series of works of Price breaks off on 

 Discocotylidae and the last four families have not been completely 

 analyzed by him but only indicated in his thesis towards his doctoral 

 dissertation (Price, 1936) and in the small article about Axine (Price, 1945). 



Without stopping at separate works concerning parts of the 

 system of monogenetic trematodes, although they have in a number of 

 cases important significance, for they will be discussed in appropriate 

 places of the exposition of our system, we shall only indicate here that 

 the last general resume'of the systematics of monogenetic trematodes 

 is the work of Sproston (Sproston, 1946) in which the system of mono- 

 genetic trematodes basically corresponds to the one proposed by Price 

 with a few exceptions. Thus, in the superfamily Capsaloidea the 

 following changes are made: Enoplocotylinae are transferred from 

 Acanthocotylidae into Microbothriidae as an independent subfamily of 

 the latter; the name of Trochopinae is replaced by Trochopodinae for 

 considerations of linguistic nature; within the limits of Capsalidae one 

 more subfamily is re-established— Encotyllabinae Monticelli 1892 with 

 the unique genus Encotyllabe Diesing, referred by Price to Benedeniinae; 

 Acanthocotylidae are removed from the composition of the superfamily 

 Capsaloidea into a special superfamily. Among the suborder of Poly- 

 pisthocotylea first of all the separation of a new superfamily Avielloidea 

 with one new family Aviellidae and the monotypic genus Aviella 

 ( =Ancyrocotyle Vlassenko) attracts attention (for the history of this 

 much-abused "group" see page 389). Further, within the limits of the 

 family Hexabothriidae, Sproston eliminates the subfamily Rajonchocotylinae, 

 including the genera which pertain to it in the subfamily Hexobothriinae 

 She apparently includes the new family Chimaericolylidae Brinkmann, 

 1942 in the superfamily Diclidophoroidea; Plectanocotylidae Monticelli, 

 1903 with two genera (Plectanocotyle Diesing and Octoplectanocotyle 

 Yamaguti) attributed by Price to Mazocraeidae is included in the family 

 Discocotylidae; from Microcotylidae the genus Protomicrocotyle 

 Johnston and Tiegs is transferred to '^''allisinae; as regards Microcotylidae, 

 this family is divided by Sproston into two subfamilies- -Microcotylinae 

 and Gastrocotylinae, lowering, by this very fact, the group in rank in 

 comparison with the system of Price and not accepting the separation 

 of Axininae; finally, for considerations of nomenclature the name of 

 Cyclocotylinae is replaced by the name Choricotylinae Sproston, 1946. 



400 



