CEPHALOPODA. 



Fig. 202. 



fibres provided for the pur- 

 pose. No sooner, therefore, 

 is the circumference of the 

 disc placed in close and air- 

 tight contact with the sur- 

 face of an object, than the 

 muscular piston is strongly- 

 drawn inwards ; and, a va- 

 cuum being thus produced, 

 the adhesion of the sucker is 

 rendered as firm as mechan- 

 ism could make it. 



(476.) Yet even this ela- 

 borate and wonderful system 

 of prehensile organs would 

 seem, in some cases, to be 

 insufficient for the purposes 

 of nature. In the powerful 

 and rapacious Onychoteuthis 

 (fig. 203 ) the cupping- 

 glasses which arm the ex- 

 tremities of their long pair 



of muscular arms are rendered still more formidable ; for from 

 the centre of each sucking-cup projects a strong and sharp hook, 

 which is plunged by the action of the sucker deeply into the 

 flesh of struggling or slippery prey, and thus a firm and most 

 efficient hold upon the seized victim is secured. Nor is this all 

 that claims our admiration in the organization of the arms of 

 Onychoteuthis : at the base of each fleshy expansion that sup- 

 ports the tenacious and fanged suckers above described is a small 

 group of simple adhesive discs, by the assistance of which the 

 two arms can be locked together (fig. 203, A), and thus be made 

 to co-operate in dragging to the mouth such powerful or refractory 

 prey as, singly, the arms might be unable to subdue ; an arrange- 

 ment which has been rudely imitated in the construction of the 

 obstetric forceps.* 



* Cyclop, of Anat. and Physiol. art. CEPHALOPODA. 



2 F 



