23 



being put into spirit that they now occupy so much of the cavity 

 that not more than one third of the body of the parent could be 

 forced into it. 



Referring to the fact that the Cephalopods hitherto found in the 

 shells of each species of Argonauta have invariably presented 

 characters as specifically distinct as those of the shells in which they 

 were found, each species of animal having appropriated to it its own 

 peculiar species of shell — a fact which extends not only to Arg. 

 Argo, Arg. tuberculata, and Arg. Mans, but also to an undescribed 

 species obtained in the Indian seas by Capt. P. P. King, R.N., for 

 which Mr. Owen proposes the name oi Arg. rufa, he is disposed to 

 believe that the shell really belongs to the animal that occurs in it. 

 On this account he speaks of the animal in question as the Arg. Mans, 

 discarding the name of Ocytho'e CrnncMi applied to it by Dr. Leach. 



In carefully describing the specimen before him, Mr. Owen cor- 

 rects some errors in the account given of the animal by its original 

 describcr, and furnishes various particulars which, from the con- 

 tracted state of his individuals, were unobserved by Dr. Leach. He 

 also adverts to the statement made by that able zoologist, that 

 in this species all the internal organs are essentially the same as in 

 Octopus : and remarks that Arg. Mans, like Arg. Argo, recedes from 

 the naked Octopods and approaches the Decapods in the structure of 

 the branchial hearts, which are provided with a fleshy appendage, 

 in the form of the appendages cf the vena cava, which are shorter 

 and thicker ; and in the relative position of the lozenge- shaped ink- 

 bag, which is not buried in the substance of the liver, but lies in its 

 anterior concavity : the inferior salivary glands are also relatively 

 smaller. The following differences, as compared with Octopus, oc- 

 cur in other internal organs which adhere to the type of structure 

 that characterizes the Octopodous tribe of the DibrancMata : the 

 laminated pancreatic bag is of a triangular form, and not spirally 

 disposed ; the two oviducts are devoid of the circular laminated 

 glands which surround them in Octopus about the middle of their 

 course ; they are also disposed in four or five convolutions as they 

 pass behind the roots of the bi-ancMte ; and they terminate at a rela- 

 tively greater distance from the base of the funnel. 



Mr. Owen then describes various portions of the internal struc- 

 ture of Argonauta ; and especially its brain, its principal nervous 

 cords, and the lateral muscles, here at their minimum of develop- 

 ment, which attain in Nautilus, as the muscles of attachment to the 

 shell, so enormous a size. 



The eggs are in nearly the same state of development as those 

 which have been described by Mr. Bauer and by Dr. Roget ; and 

 consequently afforded no conclusive proof as to the nature of the 

 connexion of the animal with the shell. In one of them, from the 

 form of the opake body contained within it, Mr. Owen for a moment 

 entertained the idea that the nucleus of the real shell might be 

 found : on tearing open, however, the external tissue, the contained 

 substance turned out to be nothing more than the yelk, separated 

 by an intervening stratum of clear fluid from the transparent mein- 



