EXPLANATION OF THE PLATES. 



PLATE XXVII. 



PIGMENT CELLS. 



Fig. 1 . Pigment cells and granules taken from off the inner 

 surface of the choroid membrane of the human eye, 

 magnified 670 diameters. 



Fig. 2. The pigment cells of the inner surface of the choroid 

 of the eye of the pig, magnified 350 diameters. 



Fig. 3. Displays the linear and branched disposition of the 

 stelliform pigment cells of the lamina fusca of the 

 eye of the pig. A similar disposition of these cells 

 also exists in the human eye, but in light-coloured 

 eyes is not strongly marked: the branches com- 

 mence on the posterior part of the lamina, mis- 

 called fusca, since in some instances it is jetty black, 

 are at first thick and closely arranged ; as they ap- 

 proach the anterior part of the eye, however, they 

 diminish in size, and are separated by distinct in- 

 tervals. This figure is magnified 100 diameters. 



Fig. 4. A. Human stelliform pigment cells of the eye, mag- 

 nified 350 diameters. B. Pigment cells of the 

 skin of the negro enlarged 670 diameters, c. Pig- 

 ment cells from the lungs magnified to the same 

 extent. 



Fig. 5. A portion of the epidermis of the negro magnified 

 350 diameters, and, viewed on its under surface, 

 the pigment cells are seen to be collected prin- 

 cipally in the furrows which exist between the 

 papillae, the depressions produced by which are also 

 represented in the figure. 



Fig. 6. A portion of the epidermis removed from the areola 

 around the nipple of a woman recently delivered, 

 and also viewed upon its under surface. It is seen 



