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TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



On preservation by killing in water and pickling in five 

 per cent, formalin, the wliole strobila is more transparent 

 and thinner in the tnrbot than in the brill, and in the 

 latter case the edges of the proglottides are very usually 

 more or less crenulated. These differences are very 

 obvious and are generally constant. The smaller head 

 of the cestode from the brill is, in particular, a very 

 striking point of difference. 



Tetraphyllidea. 

 Oncobothriidje. 

 Oncobothrium uncinatum, Kud. (Figs 12). 



Hosts : Raia metadata and R. microcellata, Cardigan 

 Bay; and R. clavata, Bahama Bank. 



Fig. 12. Oncobothrium uncinatum, Rudolphi. A : the scolex 

 seen from above, mag. 32 dia. ; B : the scolex seen from the side, 

 mag. 21 dia. ; C : hooks. 



This species has been recorded by van Beneden from 

 the coasts of Belgium as a parasite of Raia clavata, and 

 Trygon pastinaca, while Linton records it from the 

 Wood's Hole region from Trygon centrum. According to 

 van Beneden it is very rare. I have obtained five 

 specimens altogether. 



