THE STUKGEON. 



533 



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, technically called the otoliths. 



The Fishes comprised in the first order are called by the rather harsh- 

 ly-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. 



The first family, of which the common Sturgeon is a good and fa- 

 miliar example, is 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 b? set almost in the throat, the long snout appearing 

 to be entirely a super- ^__^ ^_^ 



fluous ornament. The 

 mouth projects down- 

 ward like a short and 

 wide tube, much wider 

 than long, and on look- 

 ing 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 mem- 

 brane is then peeled ofi", 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 aflfbrds so large a quantity of gelat- 

 inous matter that one part of isinglass dissolved in a hundred parts of 

 boiling water will form a stiff* jelly when cold. 



Caviare is made from the roe of this fish, and, as nearly three millions 

 of eggs have been taken from a single fish, the amount of caviare that 

 one Sturgeon can afford is rather large. 



45 -^ 



The Sturgeon {Acipenser attilus). 



