The true attaching disc of Acanthocotylidae lies on the posterior 

 end of the secondary disc on the ventral side and is equipped with 14 edge 

 and two middle hooks. 



Among Microbothriidae (Fig. 49) there is a much-reduced 

 suction-type disc with its interior surface cuticulized to greater or lesser 

 degree. The chitinous armature apparently is completely absent. 



Fig. 45. Anoncho- 

 haptor anomaluni 

 Mueller, adult 

 worm. (Accord- 

 ing to Mueller, 

 1938). 



0.1mm 



i>\ 



Fig. 46. Protoncyrocephalus 

 strelkowi Bychowsky, adult 

 worm from the gills of 

 Limanda aspera (Pall. ) from 

 the region of Yablochnoii 

 (Southern Sakhalin, Sea of 

 Japan), 



Fig. 47. Cathario - 

 trema selachii (Mac- 

 Callum), adult worm. 

 (According to Price, 

 1938). 



As regards Polystomatidae , a powerfully developed disc more 

 or less delineated from the body and provided with six suckers, 16 nnarginal 

 or edge hooks and 2 to 4 middle hooks is characteristic. The latter can be 

 absent (for instance in Neopolystoma, Fig. 15). If they exist, middle hooks 

 are located on the posterior end of the disc, whereas the edge or marginal 

 hooks, numbering six are lying on the anterior edge of the disc, and, 

 further, singly in the center of each sucker, and the remaining four on the 

 posterior edge between the first pair of suckers. 



30 



