190 
THE STURGEON. 
The hearing of Fishes appears in most cases to be dull, and some persons have asserted 
that they are totally destitute of this faculty. It is now, however, known that many species 
have been proved capable of hearing sounds, and that carp and other fish can be taught 
to come for their food at the sound of a bell or whistle. The internal structure of the ear is 
moderately developed, and there are some curious little bones found within the cavity, technic- 
ally called otoliths. 
The sense of touch seems to have its chief residence in the mouth and surrounding parts, 
the scaly covering rendering the surface of the body necessarily obtuse to sensation. The 
smell seems to be strongly developed, if it be possible to pronounce an opinion from the size 
and distribution of the nasal nerves. The brain is very small in these creatures, and from its 
shape, as well as its dimensions, denotes a low degree of intelligence. 
In the anatomy of the Fishes there are many other interesting structures, which will be 
described when treating of the particular species in which they are best developed. 
SOFT-FINNED FISHES ; CHONDROPTERYGII. 
The fishes comprised in the first order are called by the rather harshly-sounding title 
of Chondropterygii, a term derived from two Greek words, the former signifying cartilage and 
the latter a fin, and given to these creatures because their bones contain a very large amount 
of cartilaginous substance, and are consequently soft and flexible. The bones of the head are 
rather harder than those of the body and fins. 
It is necessary, before entering into any description of the different species, to premise 
that the arrangement of the fishes is a most difficult and complicated subject, in which no two 
systematic naturalists seem to agree entirely, I have, therefore, followed the course which 
has been adopted throughout the whole of this work. 
The cartilaginous fishes are again subdivided into groups, in the first of which the gills 
are quite free, and the members of this group are accordingly called by the name of Eleuther- 
opomi, or free-gilled fishes. What quality in the fishes should .give birth to such polysyllabic 
nd harsh-sounding names, is not easy to say ; but the fact is patent that not even in botany 
is the scientific terminology so repulsive as in the fishes. I shall endeavor, as far as possible, 
to avoid this technical language, and to throw the scientific descriptions to the end of the 
work, as in the two former volumes ; and the reader may feel sure when his a ttention is struck 
by a long and difficult name, that it is only used in consequence of the exigencies of the 
occasion. 
The first family, of which the common Sturgeox is a good and familiar example, are at 
once kn own by the cartilaginous or bony shields with which the head and body are at- intervals 
covered. 
In this remarkable fish the mouth is placed well under the head, and in fact seems to 
be set almost in the throat, the long snout appearing to be entirely a superfluous ornament. 
The mouth projects downwards like a short and wide tube, much wider than long, and on 
looking into this tube no teeth are to be seen. Between the mouth and the extremity of 
the snout is a row of fleshy finger-like appendages, four in number, and apparently organs of 
touch. 
One or two species of Sturgeon are important in commerce, as two valuable articles, 
namely, isinglass and caviare, are made from them. The former substance is too well known 
to need a description, and the mode of preparing it for use is briefly as follows : The air- 
bladder is removed from the fish, washed carefully in fresh water, and then hung up in the 
air for a day or two so as to stiffen. The outer coat or membrane is then peeled off, and 
the remainder is cut up into strips of greater or lesser length, technically called staples, the 
long staples being the most valuable. This substance affords so large a quantity of gelatinous 
