Shearer, Nerve Terminations in the Selachian Cornea. 2H 



perficial cells having the usual flattened scale-like appearance, 

 the layer next the corneal substance proper tall cubical column- 

 ar, and the cells of the middle layers present the well known 

 "prickle" appearance. There appears to be no membrane 

 of Bowman or of Descemet ; the posterior epithelium consists 

 of a single layer of cells. The cornea substance proper presents 

 the usual clear laminated appearance composed of about 12-14 

 sheets with corneal cells and lymph canals. 



Fig. I. Methylen blue preparation from the dog-fish cornea show- 

 ing straight unbranching inter-epithelial fibers with dark bodies 

 b. 8 mm. obj. comp. oc. 4, Zeiss, Camera. 



Examining one of these corneas properly stained and 

 fixed one is struck with the great number of nerves present, 

 their relatively straight course from the border of the cornea 

 inwards towards the center, and their unbranching course. It 

 is surprising to find how long some of the fibers are, going 

 apparently in some cases right across the whole cornea. Again 

 one notices the very regular distances they keep from one 

 another, always more or less parallel, looking under a low 

 power of the microscope like a series of ruled lines. This 

 condition is very different from what Klein describes in the frog 

 where the nerves run very irregularly, crossing one another 

 sometimes nearly at right angles. Some of these fibers give 

 off lateral branches which cannot be followed for any distance 



