THE NAUTILUS. 85 



and as the original whence artists have derived many a pretty 

 design for the car in which the sea-born Venus is made to 

 ride the ocean : 



" A shell of ample size and light, 

 As the pearly car of Ainphitrite 

 AVhich sportive dolphins drew." 



For you must have read in some of our popular works, that 

 the animal found in this shell has been supposed by many 

 of our best naturalists to be, not its own fabricator and right- 

 ful o\\iier, but an alien and vagrant cephalopod, which has 

 had the good taste to select it for its house and canoe, pro- 

 bably after having made a meal of its hypothetical inhabit- 

 ant. This opinion, which has had advocates even from the 

 days of Aristotle, has been maintained with much ingenious 

 argument, and some continue to think the question un- 

 settled ;* but I must confess that the perusal of Madame 



* Of this number is Mr. J. E. Gray, who, m a very recent publication, 

 has summed up the most important arguments in favour of the animal's 

 parasitism in the following passage : — ",The female Ocythocs are often found 

 in the shell of the Argonaut, and have hence been supposed to form these 

 shells, and as yet no other animal has been found inhabiting them ; but 

 there are several reasons for believing that the Ocythoe 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 tlie shell and keep it in its right position on the 

 body. Unlike all other mollusca, which form the shell they inhabit : First, 

 the Ocythoe is not attached to the shell by any muscle, nor has it any 

 muscle, like the bone-bearing cuttle-fish, formed for the purpose of attach- 

 ing the body to its internal shell. Secondly, the animal, when alive, does 

 not fit the shell ; so that the shell cannot have been moulded on its body, 

 as in other mollusca. Thiidly, the skin of the Ocythoe is of the same 

 texture and appearance as in the other naked cephalopoda ; and the pre- 

 sence of sand between the shell and the body appears to cause no uneasiness 

 to the animal, as it does in all other sliell-bearing mollusca, where the 

 animal immediately rids itself of the irritation so caused by covering the 

 sand, &c., with a calcareous coat. The animals found in these shells are 

 always female, and the apex of the shell is filled with very small eggs ; 

 while from the large size of the young shell, which is seen on the apex of 

 the true Argonaut, we should expect the animal wliich formed tliat shell to 

 have a large egg ; for, though the eggs of mollusca are enlarged during the 

 hatching, they are not, in any case I have observed, so much enlarged as 

 to have such a shell. 



" It is supposed by the persons who believe that tiie shell is formed by 

 the Ocythoe, that it is formed and mended when broken by the expanded 

 ends of the upper arms, which embrace the outer surface of the shell, and 

 thus keep it on the body of the animal. 



" Cranch and Adams, who have seen these animals alive, state that they 

 leave the shell when they are frightened, and that they cannot recover their 

 position in the shell after they have thus left it. 



" Mr. Adams regards the Argonaut shell as a nest formed by the female 

 to contain her eggs ; so, if this is correct, they can scarcely be compared to 

 other shells. He regards them as similar to the cartilaginous cases which 

 .Mmices and other zoophagous mollusca form to contain tlicir eggs ; but 



