B% T- ] THE HISTORY OF ANIMALS. 13 



3. All other classes of animals have eyes, except shell-fish, 

 and some other imperfect creatures, and all viviparous 

 animals except moles have eyes. A person might, however, 

 conclude from the following observation, that it has eyes, 

 though it is quite without them, for it certainly does not 

 see at all, nor has it any external eyes ; but, when the skin is 

 taken off, there is a place for the eyes, and the iris of the 

 eye is in the place which it would naturally occupy on the 

 outside, as if they had been wounded in their birth, and the 

 skin had grown over the place. 



4. The white of the eye is generally the same in all animals, 

 but the iris is very different. In some it is black, in others 

 decidedly grey, in others dark grey, and in some it is the 

 colour of the goat's eye, and this is a sign of the best dis- 

 position, and is most to be prized for acuteness of vision. 

 Man is almost the only animal which exhibits a variety of 

 colouring in the eye ; there are, however, some horses with 

 grey eyes. 



5. The eyes of some persons are large, others small, and 

 others of a moderate size the last- mentioned are the best. 

 And some eyes are projecting, some deep-set, and some mo- 

 derate, and those which are deep-set have the most acute 

 vision in all animals ; the middle position is a sign of the 

 best disposition. Some people have an eye which is perpe- 

 tually opening and closing, others have an eye always intent, 

 and others a moderately -intent eye : this last is the best dis- 

 posed ; of the others, the one is impudent, and the other a 

 sign of infirmity. 



CHAPTEE IX. 



1. THE part of the head by which we hear, but do not breathe, 

 is the ear ; for Alcmseon is mistaken when he says that 

 goats breathe through their ears. One part of the ear has not 

 received any name, the other part is called the lobe. The 

 whole ear is made up of cartilage and flesh. Internally, 

 the ear has the nature of a shell, and the last bone is simi- 

 lar to the ear itself. The sound reaches this part last, as 

 it were in a chamber. There is no passage from the ear into 

 the brain, but there is to the roof of the mouth ; and a vein 

 extends from the brain to each ear. 1 The eyes also are con- 

 nected with the brain, and each eye is placed upon a vein. 

 1 Eustachian tube. 



