306 CLASS V. CEPHALOPODA. 
notion that it was the shell of a huge night-swimming Pteropod ; others, 
that it was the branchial protector of a mollusk of homologous nature with 
the Carinaria ; and it is certainly to be regretted that the last of these 
absurd hypotheses should be tolerated by an eminent zoologist in the 
present day in the face of indisputable proof to the contrary *. 
Every doubt on the subject has been fortunately dispelled by the united 
efforts of Madame Power and Professor Owen; the former resident at 
Messina, by an interesting course of experiments on living subjects ; the 
latter, by a train of anatomical deductions from the specimens so experi- 
mented upon}. M. Rang, an intelligent traveller in Algiers, has also 
contributed somewhat to the elucidation of the subject, but the contro- 
versy was finally silenced by the observations and reasonings above 
mentioned. 
The Argonaut, like the rest of the Cephalopods, consists of two distinct 
parts ; the viscera or abdominal portion contained in a sack-like mantle, 
and the head or cephalic portion crowned with tentacles. The tentacles, 
which are eight in number, are profusely armed with a number of strong 
and powerful suckers ; there is also a funnel or vent-hole, and the breath- 
ing apparatus, under certain modifications, is not much unlike that of the 
* In the last ‘ Synopsis of the Contents of the British Museum,’ dated 1841, Mr. Gray unhe- 
sitatingly says, ‘‘ Here must be placed for the present (immediately after Carinaria, a Nucleo- 
branchiate Gastropod of his family Pterotracheide), on account of the similarity of the form 
and texture of the shell, the Paper Nautilus (Argonauta). As yet only a peculiar kind of 
Cuttle-fish, with a web to the end of the longer arms, has been found in the Argonaut shells ; 
but there are many reasons for believing that this is only a parasite, adapted by its form to 
live in such shells, as the web of the arms is used by the animal to embrace the shell and keep 
it in its right position on the body.” 
If the Argonaut shell, which obtains a very large size, bears the same relation to its here- 
assumed fabricator as the shell of the Carinaria, covering in the same manner a mere branchial 
nucleus on the back, there must, indeed, be a fleet of these animals in the Mediterranean of 
no ordinary dimensions to supply the shells that are so abundantly found there ; (more than 
a thousand specimens are before us at this moment!) they must be furnished, too, with no 
common degree of instinct to have so long escaped the vigilance of their pursuers. 
+ These specimens, exhibited by Mr. Owen to the Zoological Society in 1839, were twenty 
in number; the smallest hada shell weighing only a grain and a half, and the remainder pre- 
sented a perfect correspondency of increase up to the common-sized mature individual. 
