MALACOPTERYGII ABDOMINALES. 223 



ated 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 Siluras. 



J\L electricus, the Raasch or Thunder of the Arabs. The only species 

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

 larged 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 mus- 

 cles, 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 JLsp'edro and Loricaria. 



FAMILY IV. 



SALMONIDES. 



The Salmonides, according to Linnaeus, form but a single great 

 genus, clearly characterized 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 filled with fat, and unsupported by rays. It 

 comprises fishes with numerous ca3ca and a natatory bladder; nearly 

 all of them ascend rivers, and are highly esteemed. They are 

 naturally voracious. The structure and armature of the jaws are 

 singularly various. 



SALMO, Lin. 



The Salmon, properly so called, or rather, the Trout, has a great portion 

 of the edge of the upper jaw formed by the maxillaries; a range of point- 

 ed teeth in the maxillaries, intermaxillaries, palatines and mandibularies, 

 and a double one on the vomer, tongue, and pharyngeals; so that of all 

 fishes it is the most completely furnished with teeth. In the old male 

 the end of the lower jaw is bent up towards the palate, where a cavity re- 

 ceives it when the mouth is closed. The ventrals are opposite to the mid- 

 dle of the first dorsal, and the adipose to the anal. There are ten branchial 

 rays or thereabout. The body is usually spotted, and the flesh good. These 

 fishes ascend rivers to spawn, leaping over cataracts, &c., and are even 

 found in the brooks and small lakes of the highest mountains. 



S. salar, L. (The Salmon.) The largest species of the genus, with red 

 flesh and irregular brown spots, which soon disappear in fresh water; the 

 cartilaginous hook formed by the lower jaw is inconsiderable even in the 



