CHAPTER I 



CHIEF MODIFICATIONS OF THE EPIDERMIS OF THE 

 PALMAR AND PLANTAR SURFACES 



Great diversities of epidermic structure are found on the 

 ventral surfaces of the hand and foot of different mammals 

 when these are examined either with the naked eye or a lens. 

 The coarse arrangement of the epidermis here referred to needs 

 a short notice before the more speciahsed groupings of it are 

 described. 



The eighty-six species of mammals and eleven of birds under 

 consideration present all the chief forms of epidermic modifica- 

 tion, and these may be divided into eleven types, seven of 

 which are leading types and four mixed, as follows : 



(1) Smooth epidermis. 



(2) Corrugated epidermis. 



(3) Scales. 



(4) Nodules. 



(5) Hair. 



(6) Rods. 



(7) Papillary ridges. 

 The mixed types are : 



A. Epidermis more or less corrugated, with coarse 



transverse ridges on the digits. 



B. Corrugated epidermis with papillary ridges. 



C. Nodules with papillary ridges. 



D. Hair with coarse transverse ridges and smooth pads. 



(1) Smooth epidermis is only found in one of the eighty-six 

 mammals examined, the Earth Wolf of the Cape, Proteles 

 cristatus. 



(2) Corrugated epidermis is found in sixteen forms, and the 



