spite of the fact that the clamps of the second have only the middle hooks 

 and the first have two lateral "parentheses" in addition one should recognize 

 Chimaericolidea as the more primitive group because they have 8 more or 

 less developed clamps whereas among Diclybothriidea we already see the 

 process of the subsequent reduction of the posterior (ontogenetically first) 

 pair of clannps which extends very far in separate cases. As confirmation 



05mm 



Fig. 295. Chimaericola leptogaster (Leuckart), the ovary of an adult worm 

 from the gills of Chimaera monstrosa L. from the Norwegian Sea near the 

 Island of Sere. 



of this conclusion we can find a number of other peculiarities of Chimaeri- 

 colidea. Thus first of all, attention is attracted by the structure of the 

 cephalic end. In contrast to the majority of Oligonchoinea just as in the 

 basic nnass of the genera of Diclybothriidea in Chimaericolidea there are 

 no traces of the inception of two suckers of the buccal cavity {Fig. 53). 

 Their rather large buccal cavity opens outside on the ventral side, some- 

 what away from the anterior edge of the cephalic end. The buccal opening 

 has a weakly muscular surrounding lobe which, although sometimes acquiring 

 a sucker-shaped form it nevertheless is not separated by a special membrane. 

 The anterior end of the body does not form any outgrowths and the existing, p. 

 relatively weakly developed head glands open evenly along the entire anterior 

 edge. All this taken together represents characteristics again more primitive 

 in comparison with peculiarities of the cephalic end of Diclybothriidea, 

 Exceedingly singular and phylogenetically very interesting is the structure 

 of the ovary in both known genera of Chimaericolidae. In Chimaricola 

 according to the description of Brinkmann (Brinkmann, 194Zb) the ovary 

 is not compact but consists of a number of elongated folliculi of different 



415 



496 



