^'^'^£j^:^^^W^^ 



^ 



Fig. 67. Photomicrograph of the central (nasal) fovea of the hawk. X 50. 



Fig. 68. Photomicrograph of the depigmented fovea centralis of the chameleon. 



X 200. 



Fig. 69. Photomicrograph showing double fovea of the swallow. X 25. 



97 



