88 Trans. Acad. Sci. of St. Louis. 



the sections well enough preserved to show that there 

 are usually three layers of epithelial cells. The cells of 

 the basal layer are more or less cuboid, the next layer 

 consists of flatter cells, and in the outer layer they are 

 still more flattened. In the eyes of the adult specimens 

 where the corneal surface was well protected the corneal 

 epithelium is preserved intact and shows the same 

 arrangement. 



The corneal tissue proper shows a lamellated structure 

 with fixed corneal cells. I have not been able to find 

 any anterior uniform layer corresponding to Bowman's 

 layer, nor a posterior membrane corresponding to that 

 of Descemet in the human eye. On account of the 

 extreme shallowness of the anterior chamber in most 

 of my sections, in consequence of which the anterior sur- 

 face of the iris and the anterior pole of the crystalline 

 lens seem fairly agglutinated to the posterior surface of 

 the cornea, it was only with difficulty that I could con- 

 vince myself that the posterior surface of the cornea is 

 lined with a layer of endothelial cells'. These cells 

 appear large and flat and have a large oval nucleus. They 

 resemble so much the capsular epithelial cells of the 

 adjacent crystalline lens that this, also, helps to render 

 it more difficult to differentiate them. 



The sclerotic is quite thin and shows nothing particular 

 aside from a small amount of cartilage tissue which I 

 find not only in the larvae, but also in some of my adult 

 specimens. 



As stated above, the very darkly pigmented uveal tract 

 is in all of my sections more or less mutilated and dis- 

 integrated, and quite frequently the choroid is split in 

 two unequal parts, the inner one adhering to the retina. 

 It was, therefore, impossible to study the structural con- 

 ditions with anything like accuracy and completeness. 

 In none of my sections have I found a trace of a blood- 

 vessel in this membrane, which in the human eye is the 

 vascular coat. The ciliary body appears simply like a 

 few folds and corrugations of darkly pigmented tissue in 



