MALACOPTERYGII ABDOMINALES. 213 



SILURUS, Linnaeus. 



A numerous genus, easily recognised by its nudity, the mouth cleft in the 

 extremity of the snout, and in the greater number of the sub- 

 genera, by the strong spine which forms the first ray of the 

 pectoral. It is so articulated with the bone of the shoulder that 

 the fish can either depress itj or raise it perpendicularly, when 

 it is immoveable, constituting a dangerous weapon, wounds from 

 which are considered as poisoned, an idea arising from the fact 

 that tetanus frequently ensues. They are usually called Cat-fish. 

 S. giants, Lin. The largest fresh water fish found in Europe, and the only 

 one of this extensive genus that it possesses ; it is smooth, black, greenish, 

 spotted with black above, with yellowish white beneath; head large; with 

 six cirri ; it sometimes exceeds six feet in length, and weighs three hundred 

 pounds. It inhabits the rivers of Germany and Hungary, the lake of 

 Haarlem, Sec., and conceals itself in the mud to watch for prey. The flesh, 

 which is fat, is employed in some places for the same purposes as lard. There 

 are various subgenera. 



Is distinguished from Silurus, properly so called, by the absence of the 

 radiated fin on the back, there being nothing but a small adipose one on the 

 tail, and by the total deficiency of a spine in the pectorals, whose rays are 

 entirely soft. The head as well as the body is covered with a smooth skin ; 

 the teeth are small and crowded, and arranged in a broad crescent both above 

 and below ; there are seven rays in the branchiae, and the jaws and viscera 

 resemble those of a Silurus. 



M. electricus, the Raasch at Thunder of the Arabs. The only species 

 known ; it has six cirri, and the head is not so big as the body, which is 

 enlarged forwards. This celebrated fish, like the Torpedo and Gymnotus, has 

 the faculty of communicating an electric shock. The seat of this power seems 

 to be in a particular tissue, situated between the skin and the muscles, and 

 presenting the appearance of a fatty cellular tissue abundantly furnished with 

 nerves. From the Nile and the Senegal. 



The remaining genera of this family are Aspedro and Loricaria. 



FAMILY IV. 

 SALMONIDES. 



THE Salmon family, according to Linnaeus, form but a single great genus, 

 clearly characterised by a scaly body, with a first dorsal, whose rays are all 

 soft, followed by a second one small and adipose, that is formed of skin rilled 

 with fat, and unsupported by rays. It comprises fishes with numerous caeca 

 and a natatory bladder ; nearly all of them ascend rivers, and are highly 



