146 PROF. OWEN ON NEW AND EAEE CEPHALOPODA. 



Both dorsal and ventral brachial cutaneous folds, or "vela," are greatly developed in 

 Ommastrephes ensifer, more especially in the third pair of arms (PI. XXVIII. fig. 1, 3) ; 

 and in these the disposition of the muscular fibres for contracting or folding the web or 

 net is indicated through the integument (ib. a). A fasciculus is continued from the base 

 of the peduncle of each sucker of the outer row, which extends with a slight curve 

 toward the free border of the ventral web, and expands as the fibres spread out to ter- 

 minate in that border. 



In the extent of this brachial membrane the present species of Decapod comes nearest 

 to that form of Octopod (the Argonaut) in which the tegumentary expansion of a certain 

 pair of arms is in excess. In Argoiiauta the so-called " sails," we know, relate to the 

 formation and support of a rudimental shell. Although no such relation can be predi- 

 cated of the brachial vela of our female Ommastrephes ensifer, it may be a question 

 whether they are equally developed in the male. Should he similarly possess them, it 

 may then be supposed that, by means of such brachial developments, the fish which 

 has been struck by the spines of the horny rim of the suckers may be enveloped by 

 the webs, which can be so wrapped about it as more effectually to retain it till the other 

 acetabuliferous arms are brought to bear upon the prey. 



Cephalopods have been sometimes figuratively called " sea-spiders;" and in the pre- 

 sent species we see something superadded to the prehensile spiny-crowned suckers 

 analogous to that with which the air-breathing Octopod envelops the struggling wasp 

 or blue-bottle in a rapidly outspun web. 



In the mechanism for catching its finny prey exemplified in the above-noted cha- 

 racters of Ommastrephes ensifer, we recognize a power of obtaining a supply of nutri- 

 ment favourable to the acquisition of the bulk which the subject of the present descrip- 

 tion had attained. If, in place of the spiny hoop, each sucker were armed with one 

 large hook, an oceanic swift-swimming Cephalopod would have increased power over the 

 shoals of fishes whence its nutriment was derived, and still greater dimensions might be 

 concomitantly attained. 



Genus Ontchoteuthis, Lichtenstein '. 



A much larger Cephalopod, parts of which have come under my observation, is that 

 which received the following notice in Hawkesworth's ' Account of the Voyages of Dis- 

 covery in the Southern Hemisphere, successively performed by Commodore Byron and 

 Captains Wallis, Carteret, and Cook' ^. 



In the 2nd volume ("Lieut. Cook's Voyage "), H.M.S. 'Endeavour' having rounded 

 Cape Horn, and being then in latitude 38° 44' S. and longitude 110° 33' W., is the fol- 

 lowing entry, of date between the 1st and 8th of March, 1769 : — 



' Das zoologisclie Muaeum der Univereitat zu Berlia, no. xv. (1818), p. 1592. 

 ' In 4 vols. 4to, 1773. 



