12 FISHES. 



Roach have only a few strong teeth in the throat, 

 and a single flat one above ; and the Sturgeon, 

 the Pipe-fish, and the Sandlance, are entirely 

 toothless. 



The blood, as already observed, commonly 

 takes the temperature of the surrounding ele- 

 ment ; in some of the swift oceanic Fishes of 

 the Mackerel family, however, such as the Tunny 

 and the Bonito, the blood is found to be 10° 

 higher than the temperature of the surface of 

 the sea, even within the tropics : the flesh of 

 these Fishes is dark and dense. The blood-disks 

 are sometimes circular, sometimes oval ; they are 

 larger than those of Mammalia and Birds ; smaller 

 than those of Reptiles, and especially than those 

 of Amphibia. 



The brain is small, and is divided into a suc- 

 cession of lobes or ganglionic masses, " most of 

 them exclusively appropriated to the function of 

 a nerve of special sense." The senses are pos- 

 sessed probably in very different degrees. Touch 

 is considered to be feebly exercised ; but the 

 thick and fleshy lips of the Wrasses, the whip- 

 like filaments of the Anglers, the beards of the 

 Cod and Barbel, and the long fiexible fingers 

 in the pectoral fins of the Gurnards may be the 

 seats of special sensations of feeling. Taste is 

 even still more dubious. The bony character of 

 the mouth, and the manner in which the tongue 

 is often covered with teeth, combine with the 

 circumstance that the food is almost invariably 

 swallowed whole the instant it is seized, — to for- 

 bid the supposition of acute taste. 



The sense of smell is probably possessed in 

 considerable perfection by Fishes. The olfactory 



