380 FISHES. 



level with their head. It is probable that the vibrations of the 

 water may communicate a sensation analogous to that of sound. 



The sense of taste in fishes cannot be delicate, as their tongue 

 is often osseous and furnished with teeth or other hard covering ; 

 they are destitute of salivary glands ; and the greater part swallow 

 their food without maceration. Neither is the sense of touch very 

 acute, as in most the body is covered with scales, and in all the 

 organs of prehension are wanting. The cirri or filamentous fleshy 

 processes of some families may perhaps supply the imperfections 

 of their organs of touch. 



In the greater number of fishes the intermaxillary bone forms 

 the margin of the upper jaw, having behind it the maxillary 

 or labial bone. The palatine arch, composed of the palate bones, 

 the two pterygoid processes, the zygomatic process, the tympa- 

 num, and the squamous portion, forms, as in birds and serpents, 

 a kind of interior jaw, and furnishes behind an articulation for the 

 lower jaw, which has two bones on each side ; but these pieces are 

 reduced to the smallest number in the Chondropterygii. The 

 teeth of fishes present many varieties. Some have none at all, 

 and in others the jaws are so hard that they form a kind of solid 

 beak ; in some these teeth are pointed, edged, crenated, or flat ; 

 and in others they are placed on the lips, the jaws, the palate, 

 the tongue, the gullet, or in all these parts at the same time. 

 The stomach is almost always simple, and the intestinal canal 

 short, as in carnivorous animals ; the liver is very large ; and 

 there is but one opening for rejected matters, the milt of the 

 male and the ova of the female. 



The sexes in fishes are in the greater portion in separate indi- 

 viduals. The ova are generally impregnated by the male after ex- 

 trusion, and the young are developed without the care of the 

 parent. The male is known, besides other distinctions, by the 

 presence of the testes or milt, and the females by the ovary or 

 roe, which both occupy the same relative place in the body of the 

 animals. Those are said to be viviparous in which the ova 

 are matured, and the young developed before extrusion. In 

 the developement of the embryo, the heart first appears, after- 

 wards the spine, eyes, and tail. Of the organs of motion the 

 pectoral fins first appear, followed in succession by the caudal, 

 dorsal, and anal fins. 



