32 



VISION 



Photo courtesy of Constance Warner 

 Light-adapted eye of the blacktip shark, Carcharhinus limatus (Valenciennes)— Car- 

 charhinidae— showing vertical slit pupil entirely contracted except for the apparent 

 stenopaic aperture or pinhole at the bottom. Plate No. IA 



Photo courtesy of Constance Warner 

 Partially dark-adapted eye of the same blacktip shark with the iris dilated to a circular 

 form. Plate No. IB 



