EYES OF BLIND VERTEBRATES OF NORTH AMERICA. 6l 



The best results were obtained from those imbedded in paraffin 

 and celloidin. Several methods of staining were used ; iron 

 haematoxylin with eosin as a counterstain gave the best results. 

 The more modern methods of treating the retina with silver could 

 not be applied for lack of fresh specimens. On account of the 

 extreme toughness of the cuticle it was impossible to get com- 

 plete series of sections. For comparison I have examined the 

 eye of Anolis carolincnsis. 



GENERAL ACCOUNT OF THE EYE. 



The eye of AnipJiislnzna appears indistinctly as a small black- 

 spot beneath the ocular plate (Fig. i). In a specimen 225 mm. 

 in length, the eye is 352 a beneath the surface, 420 ft in width 

 and 360 [J. in depth. The conjunctival sac 

 is 1 1 6 IJL in diameter. The conjunctiva is 

 very thin over the cornea, but measures 4;^ 

 in thickness over the anterior part of the sac. 



The dermis and epidermis have the same 

 structure over the eye as over the regions FK . l 



near by. This corresponds with what 



Eigenmann ("The Eyes of Rhineura floridana" 1902) found in 

 Rhincnra, although the eye of RJiinenra is a much more de- 

 generate organ than the eye of Amphisbcena. To what extent 

 the eye has degenerated from a more elaborate structure I am 

 unable to say. Few organs are stationary and this one is prob- 

 ably still in process of reduction. I have been unable to obtain 

 the young, and there is no means of finding out from the adult 

 whether the eye is degenerating at present or not. In each 

 specimen examined the eyes appeared in about the same state of 

 degeneration. 



The eye measures 1,224/11 in circumference and the pupil 104^ 

 in diameter. The uveal part of the iris on each side of the pupil 

 measures 250^. The pupil and iris occupy 49.3 per cent, or 

 very nearly half of the entire circumference. 



Harder' s gland is very much larger than the eye. In a cross- 

 section through the central portion of the eye, the antero-posterior 

 diameter is approximately three times and the medio-lateral dia- 

 meter four times the medio-lateral diameter of the eye. It is 



