CLASS III. GASTEROPODA. ORDER V. NUCLEOBRANCHIATA. 57 
Argonaute, though in a separate class, Heteropoda, upon the presump- 
tion of their being allied to the Cephalopoda. Now, however, no one 
attempts to argue that there is any resemblance between the Carinarize 
and the cephalopodous mollusks; their affinity with the Argonauts is 
contested only by those, who, in still foolishly regarding the animal 
usually found in the well-known papyraceous shell as a parasite, believe 
its true owner and fabricator to be probably some huge nucleobran- 
chiate. In our observations on the genus Argonauta, we shall endea- 
vour to show more fully how entirely this extravagant hypothesis has 
been refuted by the anatomical discoveries and experiments of Professor 
Owen. 
The shell of Carinaria may be described as being conical, cap-shaped, 
very thin, hyaline, and somewhat compressed at the sides ; the vertex is 
very much attenuated, and is inflected into a very minute heliciform 
spire, exhibiting the formation of the shell in embryo; the back is fur- 
nished with a keel, composed of two distinct laminz, belonging as it were 
to each half of the shell, and it is either simple or dentated, in a direct 
ine from the vertex to the aperture; the aperture is oblong, very large 
and entire. ‘There is no appearance of any muscular impression. 
The Carinariz are very abundant in the Mediterranean and Indian 
Seas ; they swim about in numbers together, but are seldom to be seen 
except at night. 
Examples. 
Pl. CLVIII. Fig. 1 and 2. 
CarinariaA MEDITERRANEA, Sowerby, Genera of Shells, No. 34. 
Pl. CLVIII. Fig. 3 to 5. 
Carrinaria Gracitis*, Nobis, Annals and Mag. Nat. Hist., April 1842. 
* This magnificent shell is in the collection of the Rev. Mr. Stainforth. 
VOL. Il. I 
