TO UCH AND SIGHT OF FISHES. 265 



" bait-mill," and by its aid the contents are reduced to a 

 kind of paste, which is thrown into the sea to attract the 

 fish, which are then caught by lines with hooks, having a piece 

 of polished pewter attached as a lure. In all fishes, nostrils 

 or external openings are very apparent, and in these the 

 nerves of smell are distributed. 



Taste in fishes (as in animals who almost invariably 

 swallow their food without mastication) cannot be very 

 acute, since their tongue is in great part bony, and is often 

 furnished with teeth and other hard coverings. 



The organ of touch is in general as imperfect as that of 

 taste: without prolonged members, and flexible fingers 

 capable of grasping, they can scarcely explore the forms of 

 objects by any other means than by their lips. Certain little 

 fleshy tendrils which some fishes possess may supply the im- 

 perfections of touch in the other organs. 



The bodies of most fishes are covered with small brilliant 

 plates of a horny nature called scales, but in some kinds 

 these are wanting, as in the turbot and others, in place of 

 which are found bony protuberances in some species, and in 

 others a very smooth skin without scales, and covered with 

 a thick gelatinous secretion from the body. The scales con- 

 sist of a substance chemically resembling the composition of 

 bones and teeth. They usually overlap each other like tiles. 

 Some are very thick forming a kind of armor. 



In general, fish have large eyes, and in particular the 

 pupil is very broad and open, as might be expected in crea- 

 tures who require great powers of vision in the deep, where 

 light penetrates but scantily. The eyes have no real eye- 

 lids, the skin passing over them mostly in a transparent form, 

 to admit light; and they are sometimes opaque or dense. 

 Home varieties of fish, whose eyes are fixed on the upper 

 surface of their bodies, cannot see what prey they swallow ; 

 others have no outward indication of an eye. *' No tear 

 moistens, no eyelid shelters or wipes the surface ; the eyes 



