153 



MaVny animals have muscles to move the eye, and 

 obvert it to the object. Fishes have none ; but for 

 amends they have many little protuberances finely 

 ranged on their large bulging eyes, by which number- 

 Jess rays of light are deflected from objects above, be- 

 neath, and on either side. Yea, some hundreds of 

 these protuberances are curiously ranged on theconvex 

 eye of a Flesh-fly. 



Scorpions have above a hundred eyes; an Epheme- 

 FOII fly full two thousand. 



In other creatures which have only two eyes, the 

 want of motion therein is supplied by their eyes pro- 

 tu be rating into hemispheres, each being a vast num- 

 ber of segments of a sphere. 



The eyes of a Cameleon resemble a convex glass set 

 in a round socket, which he turns backward and for- 

 ward without stirring the head, and commonly one a 

 contrary way to the other. 



Lastly, Moles living under ground, have not so 

 much need of eyes as other creatures : yet they have 

 eyes, but exceeding small, far in the head, and co- 

 vered with strong hair. When they are above ground 

 they can put the:-i forth beyond the skin, and draw 

 them back at pleasure. 



Another circumstance relative to the eye is highly 

 remarkable. As- we use various apertures to our optic 

 glasses, so nature has made a far more com pleat pro- 

 vision to admit enough, and not too much light into 

 th eyes of animals, by the dilatation and contraction, 

 of the pupil. And this, in divers animals of divers 

 forms, is according to their peculiar occasions. Li 

 some it is round, particularly in man 5 that being the 

 most proper figure for the position of our eyes, ani 

 the nse we make of them both by day and night. In, 

 some animals it is of a longish form, m some transverse, 

 with its aperture large (an admirable provision for fi.eir 

 seeing sidc-\vays>) and thereby avoiding many incoiu 

 yenicncies, as well as a help for g.thering their food 

 on the ground, whether by day or night. In others,' 

 that aperture is crcct ? and also capable of opening wide 



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