146 PROF. OWEN ON NEW AND RARE CEPHALOPODA. 
Both dorsal and ventral brachial cutaneous folds, or “ vela,” are greatly developed in 
Ommastrephes ensifer, more especially in the third pair of arms (Pl. 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 cut 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 Argonauta 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 OnycuorTeutuis, 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.ML.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 Ist and 8th of March, 1769 :-— 
? Das zoologische Museum der Universitit zu Berlin, no. xy. (1818), p. 1592. 
3 In 4 vols. 4to, 1773. 
