xxv] 



CHEIROPTERA 



707 



shown that the eyes of Bats, although apparently normal are 

 really degenerate, that in fact the layer of visual rods in the retina, 

 which is the special organ of light-perception, is most imperfectly 

 developed. To compensate for this we find, in some species, the 



FIG. 357. Female and young of Xantharpyia collaris. From Sclater. 



outer ear, in others the skin around the nostrils, in others 

 again the skin on the lips and chin, developed into curious out- 

 growths richly supplied with nerves. By means of these sense- 

 organs Bats are enabled to avoid obstacles, and a blind Bat, let 



452 



