This singular animal is rarely taken, on account of its delicate and
perishable substance; it is found in the Southern Ocean. It will be
seen, on referring to the engraving, that the shell which it bears
merely covers a portion of its body, that in which the most material
organs of the animal are found, namely, the heart and the branchiæ, or
organs of breathing. These are most curiously placed on the upper part
of its body, projecting from it and protected by a delicately white
and transparent shell, shaped like a little cap, and of a substance
resembling glass. The creature is able to enlarge its body by filling
it with water, and in swimming the back is undermost. The shell, which
seldom exceeds an inch in length, has been sought after by collectors
with great assiduity, and has, at times, fetched as much as ten guineas
at a sale; a perfect specimen is very rarely met with. There is a wax
model of one of these shells in the British Museum, nearly two inches
wide.
[Illustration: THE GLASSY CARINARIA, (_Carinaria vitrea_.)]
_ORDER CEPHALOPODA._
The Cephalopods have been so named by Cuvier, from being furnished
with a kind of inarticulated arms which surround the head. We find
among this class some of the most singular productions of the waters;
they differ materially from each other, and have been separated into
three groups; first, those without any external shell, as the Sepia;
secondly, the inhabitants of a shell without any divisions, as the
Argonaut; and, thirdly, those whose shell is divided into numerous
chambers, as the Nautilus.