BOOK XI. Lv. 152-LV11. 156 



eyes have less keen sight than those whose eyes are 

 moist. It is stated that if one removes the eyes of 

 young snakes and swallow chicks, they grow again. 

 The eyes of all insects and of creatures with a covering 

 of shell move Uke the ears of quadrupeds. Those 

 with fragile coverings have hard eyes. All such 

 creatures, and also fish and insects, have no eye- 

 Uds and do not close their eyes ; withal the eye is 

 covered with a membrane that is transparent Uke 

 glass. 



LVI. Himian beings have eyelashes on both eye- Theeye- 

 Uds. Women actuaUy have them dyed every day : 

 such is their desire to achieve beauty that they colour 

 even their eyes ; but really the lashes were bestowed 

 by nature for another purpose, as a sort of fence 

 to the sight and a barrier projecting against insects 

 meeting the eye, or other things accidentally faUing 

 into them. It is said that sexual excess causes them 

 to drop off, not undeservedly. None of the other 

 species have them excepting those with hair on the 

 rest of the body as weU, but quadrupeds have them 

 only on the upper Ud, birds on the lower, as also do 

 creatures with a soft skin, for instance snakes, 

 and oviparous quadrupeds, for instance Uzards. 

 The ostrich is the only bird with lashes on both eye- 

 Uds Uke a human being. 



LVII. Not aU species have eyeUds either, and also Theei/elidj. 

 only viviparous creatures can wink. Tlie heavier 

 bii'ds close the eye wth the lower Ud, and also wink 

 with a skin that covers the eye from tlie corner. 

 Pigeons and similar birds close the eyes with both 

 Uds. But oviparous quadrupeds, such as toi-toises 

 and crocodiles, do so only with the lower Ud, without 

 any winking because their eyes are extremely 



529 



