66 PHYSIOLOGY OF FISHES. 



through it : a gelatinous fluid, glaiiy, of a similar 

 character to the white of an egg, seems both to 

 suspend the bone, and also afford a proper bed for 

 defending the nerves. Though comparative anat- 

 omists are not precisely satisfied as to the office 

 they sustain, it is pretty generally conceded that 

 they are a part of the organ of hearing. If, how- 

 ever, our readers will examine the diagram we 

 have given of the labyrinth of the fish's ear, which 

 corresponds very nearly with the vestibule and se- 

 micircular canals of the human ear, he will per- 

 ceive that the brain bones are entirely unnecessary 

 to the perfection of the organ. Their use is not 

 understood.* . 



* Since the compositor completed the preceding pages, in 

 which it is remarked that fishes are without eye-lids, a speci- 

 men has come to hand, of a small fish, seven inches in length, 

 from Africa, the mounting of whose eyes on the top of the 

 head, bears some resemblance to the anableps, covered by a 

 regular pair of eye-lids. This must be regarded as belonging 

 to an unknown genus. In a small shark, too, we have detect- 

 ed the nictitating membrane, organized much as it is in the 

 owl, and other night-seeing birds. 



