The presence of a sharply individualized disc bearing hooks is 

 characteristic for all species. With this, both the disc itself and the hooks 

 lie in a bilaterally symmetrical fashion on it, which undoubtedly bears the 

 primary character. Apparently the disc of the adult forms corresponds to 

 the larval one which has grown strongly in the postembryonic period. In Proto- 

 microcotyle and Bilaterocotyle attaching clamps of the usual discocotyiid- 

 type lie above the disc on the ventral side, whereas in Lethacotyle they are 

 totally absent (Manter and Prince, 1955). The clamps are located in one 

 row and there are 4 of them all together in Protomicrocotyle, whereas in 

 Bilaterocotyle there are 6 lying in two vertical rows by 3's. The drawings 

 of Meserve, 1938 show that there is a special zone around the clamps 

 strongly resembling the embryonic tissue which forms around the clamps 

 of Microcotyle in the process of development. Nevertheless, we do not have 

 sufficient basis to suppose that we deal here with underdeveloped individuals 

 in spite of the fact that this is indicated by the relatively small sizes of the 

 clamps in comparison with the middle hooks of the disc. 



It is very interesting but strange that in B. pacifica, B. chiro- 

 centrosus and L. fijiensis there is a slit-shaped depression of unknown 

 origin on the side of the body and somewhat above the disc which gives the 

 body a sharply asymmetrical appearance. Just what it constitutes is not 

 clear. Judging by the drawing of MacCallum (MacCallum, 1918a), P. 

 mirabilis does not have this depression. The internal structure of the last 

 species resembles that of Microcotyle; however, the vaginal duct is single, 

 armed and apparently located in the same way as in both other species. As p. 445 



has already been indicated, the correlation between the testes and the ovary 

 is characteristic of the latter. 



As a whole, one can say that the representatives of the present 

 family are undoubtedly very aberrant forms having a number of prinaitive 

 traits on one hand and the elements of "embryonization" on the other. We 

 think that their separation into an independent family is justifiable although 

 demanding further substantiation. At any rate, one can say with certainty 

 that the attribution of the genera of Protomicrocotylidae to Valisiinae 

 (=Anthocotylidae in the present work, see page 426), as is done by Sproston 

 in her re'sume'' is not supported. 



7. Family Gastrocotylidae Price, 1943 



(Figs. 7, 3-12, C) 



Discocotylinea, of middle and large sizes. The attaching 

 apparatus consists of 2 (?) to 3 pairs of hooks and of numerous clamps. 

 Usually there is one pair of edge and 2 pairs of middle hooks located on 

 the posterior end of the disc, more seldom one pair of middle hooks lies 

 on the disc itself closer to its upper terminal or even on the lower end of 



533 



