ICHTHYOLOGY. 555 



place in a frozen state, which revive on being thawed. So is it, 

 according to Dr. Richardson, with the Grey Sucking Carp. 

 Gold fishes which have been thawed out of a solid body of ice, 

 have completely revived. 



Species which live near the surface of the water, have less 

 tenacity of life than those which seek the deep waters. Mack- 

 erel, Salmon, Trout, and Herrings, of the former kind, die almost 

 as soon as they are taken out of the water; while Carp, Eels, 

 Tenches, Skates, and the Flat-fishes, which live near the bottom, 

 and have a low standard of respiration, and a high degree of mus- 

 cular irritability, with less necessity for oxygen, sustain life for 

 sometime after they are taken out of the water, and their flesh 

 continues good for several days. 



The Eels, Muraenida, and the Blade-eels, Ophidiada, show 

 extraordinary tenacity of life ; even removal of the skin, and the 

 division of the body into parts, not immediately producing death. 



The flesh of the larger part of fishes is useful for food ; though 

 that of some species is somewhat indigestible. Fish of fresh- 

 water are more generally edible than those of the sea; but as a 

 whole, are not so savory. Fishes are also valuable for other 

 purposes: some for the oil which they yield; the air-bladder of 

 the Sturgeon furnishes the isinglass of commerce ; the roes of 

 the Sturgeon, Pike and some other fish, furnish caviar; the sha- 

 green skin of some Placoids is employed for polishing and for 

 making ornamental coverings. The bones are used for fish- 

 hooks and other purposes. 



The first scientific CLASSIFICATION of Fishes is that of Artedi, 

 which was made in 1738 ; the next, that of Linnaeus, made be- 

 tween twenty and thirty years later. 



The Classification of Cuvier is generally adopted, and the one 

 to which the Chart most nearly conforms. The entire class 

 of Fishes is first divided into OSSEOUS and CARTILAGINOUS. 



The OSSEOUS FISHES are sub-divided into SPINE-RAYED and 

 SOFT-RAYED. 



They are also arranged into three sections, I. Pectinibran- 

 chii, which have the ~branclii(&, or gills, in continuous, comb-like 

 ridges, and include all the ordinary and typical fishes. This 

 section is comprehended in two orders. 



I. ACANTHOPTERYGII, (Gr. spine-rayed,) distinguished by' 

 having the anterior part of the dorsal, anal, and ventral fins, 

 furnished with simple, spiny rays. The Perches, Mullets, Gur- 

 nards, Mackerels, &c., belong to this order. 



II. MALACOPTERYGII (Gr. soft-rayed,) having all the fin rays 



