EXPLANATION OF THE PLATES. 



hairs, and the apertures of the sudoriferous and 

 sebaceous glands. .Magnified with a simple lens. 

 Fig. 6. A piece of the same magnified 100 diameters, show- 

 ing that each line is a furrow or groove, a provision 

 which allows of a very great extension of the epi- 

 dermis. 



