Slonaker, Eye of the Mole. 347 



lens or in the opposite direction. All possible positions be- 

 tween these two extremes are found. This confusion or lack 

 of order in the arrangement is no doubt due to the shrinking of 

 the eye, or to the development of the retina more rapidly than 

 the sclerotic coat. 



The Eye of the Adult. 



Owing to the dense fine fur the eye of the adult is seldom 

 seen in a hasty examination. But when the fur is removed or 

 parted at the right place a small dark area is easily perceived 

 which marks the position of the eye. A minute darker point 

 in the center of this dark area is the eye cleft. It is so small 

 that with the naked eye one can locate it only with difficulty. 



The conditions found in the adult are very similar to those 

 described in the young at birth. The eyelids are fused together 

 so completely that I was unable to open the cleft sufficiently to 

 see the eye. The cleft meets the eye at such an angle (Fig. 16, 

 17) that should light enter it would not be along the axis of 

 vision. There is a marked difference in this respect in the eye 

 cleft of the European mole. It is described by Kohl as 

 approaching the eye along the axis of vision. Light might 

 thus enter it and pass into the eye in a normal manner. The 

 thickness of the lids or integument over the eye is .31 mm. 



When the integument is removed the eye appears as a 

 small, black, rounded body, almost one millimeter in diame- 

 ter. It approaches a sphere in shape, but is not nearly so con- 

 stant in form as found in the young at birth. Many of the 

 sections of the eye show these departures very distinctly 

 (Plates XIX and XX). Doubtless some of this apparent dis- 

 tortion is due to the action of the reagents. Figures 1 1 and 

 12 show distortions which were no doubt caused by the killing 

 fluid. These were hardened in 10% nitric acid. 



The equatorial and axial dimensions of eyes preserved in 

 different fluids used are shown in Table i. 



