HISTORY OF FISHES. 



BOOK I. 



OF FISHES IN GENERAL. 1 



CHAP. I. 



INTRODUCTION. 



THE ocean is the great receptacle of fishes. 

 It has been thought, by some, that all fish 



1 Fishes (says professsor Blumenbach, in his Manual 

 of Natural History) are those animals which possess red 

 cold blood, which moves by means of true fins (with 

 bony or cartilaginous fibres,; and which breathe by true 

 yillf lying deep at each side of the neck; and not, as in 

 tlie larvte of frogs, &c., projecting beyond it. I say 

 true gills and tme fins, in order to distinguish them 

 from organs to a certain degree analogous in young 

 frogs, salamanders, &c. 



These gills (branchiae, ,) in fishes, almost perfectly 

 supply the place of lungs. They are placed on each side 

 behind the head, for the most part under one or more 

 large semilunar plates, hence called opercula Iranckialia, 

 and in most instances connected with the membrane 

 of the gills, mcmlrana branchiosfega. The gills them- 

 selves are filled with innumerable very delicate vessels, 

 and are mostly divided on each side into four layers, 

 which somewhat resemble the beard of a quill, and 

 which are attached at their bases to a corresponding 

 number of little bones. 



Respiration, which fishes are nearly as incapable of 

 dispensing with as those animals which possess lungs, is 

 in them effected by introducing the air, which the water 

 holds in solution, through the mouth into the gills, and 

 then expelling it again through the branchial, (apertura 

 branchialis y) consequently not by inspiring and expir- 

 ing through the same passages, as in those animals which 

 possess lungs. 



Not having lungs, it is evident that they cannot have 

 any voice, although some, as Coitus calaphractcs, Cobitis 

 fossttis, &c., can make a noise. 



The form of the body in fishes, in general, is infinitely 

 more varied than in quadrupeds and birds. In most, 

 however, the body has a vertical direction, i. e. is flat- 

 tened at both sides, (corpus compresswn) ; in some, on 

 the contrary, as the rays, it is horizontal and extended 

 laterally (corpus depressum) sive plagioplateum) ; in 

 others, as the eel, &c., it is more rounded ; in others, 

 prismatic or quadrangular, &r.. In all, the head and 

 trunk are connected immediately, without being sepa- 

 rated by a neck. 



With only a few exceptions, fishes are covered with 



are naturally of that salt element ; and that 

 (hey have mounted up into fresh water by 

 some accidental migration. A few still swim 

 up rivers to deposit their spawn ; but of the 

 great body of fishes, of which the size is enor 

 mous, and the shoals are endless, (hose all 



scales ; in the osseous fishes the scales are real, are 

 formed of a peculiar substance, and in different species 

 present a great number of varieties in point of form, 

 marks, and colours, which latter sometimes shine like 

 gold and silver. On the other hand, the cartilaginous 

 fishes, in general, are covered with several bone-like 

 plates, hook-shaped prickles, &c. The scales are cov- 

 ered externally with a kind of slime, which appears to 

 be in a great measure excreted from small cavities, 

 which, in most fishes, are placed in a line along each 

 side of the body. 



The fins, the organs of motion in fishes, in which a 

 very great power of reproduction lias been remarked, 

 consist of their bony or cartilaginous spines or rays, con- 

 nected together by a particular membrane, fastened to 

 a bone, and set in motion by certain muscles. They are 

 called, according to their position, the upper dorsal fins; 

 those at the side, behind the gills, pectoral fins ; those on 

 the belly in front of the anus, abdominal fins ; those 

 behind this opening, anal fins ; and lastly, those on the tail, 

 which always have a vertical direction, caudal fins. The 

 flying-fish, as they are called, have very long and stiffpec- 

 toral fins, by means of which they can raise themselves 

 above the surface of the water, and fly for a short time. 



Another auxiliary in the motion of fishes, particularly 

 in rising and sinking, is the swim-bladder, with which 

 fresh-water fish in particular are supplied, and which 

 communicates by a particular canal, (ductns pncumaticus) 

 generally with the oesophagus, seldom with the stomach. 



With regard to their place of abode, fishes in general 

 are divided into sea-fish and iresh- water fish. Many 

 can live for some time out of water, as the eel, Mur.Tiia, 

 &c. Others in hot mineral springs. 



Mot fishes, especially those of the sea, are nocturnal 

 animals, that is, they are active during the night, and in 

 the day remain in a state of repose. Hence the inhabi- 

 tants of islands and coasts, who live on fish, choose the 

 night for catching them. 



A great many species of fish change their place of 

 abode at certain seasons of the year. Many sea-fish 

 ascend the months of rivers and creeks to spawn ; many, 

 as the herring for instance, in the North Atlantic, make 



