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 tliat 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 suiTounding parts, 

 the scaly covering rendeilng the surface of the body necessaiily obtuse to sensation. The 

 smell seems to be strongly developed, if it be possible to pronounce an opinion fi-om 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 Pishes there are many other interesting structures, which will be 

 described when treating of the particular species in which they are best develoj)ed. 



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 ai'e 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 difiicult and comi^licated subject, in which no two 

 systematic naturalists seem to agree entirely. I have, therefore, followed the course which 

 has been adopted throughout the wliole 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 Eleuthei*- 

 opomi, or free-gilled fishes. What quality in the fishes should give birth to such polysyllabic 

 and 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 attention 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 Sttjkgeon is a good and familiar example, are at 

 once known 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 ajipearing 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 tliera. 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 



