114 FISHES. 



often other small bones between the muscles to 

 assist their motion. 



The sight of fishes is perhaps the most perfect 

 of all their senses. The eye, in the greater part 

 of them, is covered with the same transparent skin 

 that covers the res' o{ the head. The use of this 

 is, probably, to defend it in the water, since there 

 are no eyelids. The globe is somewhat depressed 

 in front, and it is furnished behind with a muscle, 

 which serves to lengthen or flatten it, according to 

 the animal's necessities. The chrvstalline humour, 

 which in quadrupeds is flattened, is in fishes nearly 

 globular. The eyes are usually thought to be im- 

 moveable, but gold fish have been observed appa- 

 rently to turn their eyes in their sockets, as their 

 occasions require. — These fish take little notice of 

 a lighted candle, though applied close to their 

 heads ; but on any sudden stroke against the stand, 

 on which the bowl containing them is placed, they 

 flounce about, and seem much frightened. This is 

 more particularly the case when they have been 

 motionless, and are perhaps asleep ; from their eyes 

 being always open it is not, however, easy to dis- 

 cern when they are sleeping and when not. 



In fishes the organ of hearing is placed on the 

 sides of the skull, or the cavity that contains the 

 brain; but, differing in this respect from that in 

 quadrupeds and birds, it is entirely distinct and 

 detached from the skull. In some fishes, as those 

 of the Ray kind, the organ of hearing is wholly 

 surrounded by the parts containing the cavity of 

 the skull: in others, as the Salmon and Cod, it is 



