A BLIND SNAKE FROM CUBA. 267 



A conjunct! val sac is present with a diameter at least as great 

 as the greatest width of the eye bulb. The conjunctiva, which 

 forms this sac, is very thin over the cornea and next to the 

 brille where it measures .003 mm. At the edge of the sac, it is 

 differentiated into glands, the fornix conjunctiva, and measures 

 .016 mm (Figs. 3 and 4). 



In horizontal section, the eye axis is seen to be turned forward 

 about 30 away from a line at right angle to the horizontal axis 

 of the body. 



Eye muscles are present, but from the sections used, the exact 

 number could not be determined. 



Minute Anatomy of Eye. 



Clioroid and Sclera. The dense pigmentation makes it impos- 

 sible to distinguish between the different coats at every point. 

 Beyond the retina with its pigment layer is an open vascular 

 space and this is followed by another dark layer, the two to- 

 gether representing the choroid. The choroidal pigmentary 

 layer seems to consist of long fibers circularly arranged. The 

 sclera can be followed by starting with the outer covering of the 

 optic nerve and tracing its continuation about the eye. 



Iris and Ciliary Processes. Here again the pigmentation 

 makes it difficult to determine the structure. Both iris and cil- 

 iary processes are present, for the black layer extends over 

 the anterior surface of the lens, leaving a pupil equal in diameter 

 to about one fourth of the circumference of the lens. At points 

 near the equator of the lens this dark layer is enlarged into the 

 ciliary processes and in connection with the capsule helps to hold 

 the lens in place (Figs. 3 and 4). 



Cornea. This structure is present and can be traced to the 

 region of the ciliary processes. 



Lens. A large lens is present, its depth being equal to about 

 two fifths of the eye depth. From the sections little could be 

 determined about its structure. A well-developed capsule sur- 

 rounds it (Fig. 7). 



Retina.- -The same layers are present that are found in snakes 

 in general, but the comparative thickness of the various layers is 

 different. In the garter snakes, for instance, the retina is of a 



