SKIN. 



3*3 



Epidermis. 



Corium. 



glands. These are widely distributed through the skin; locally the ecto- 

 derm forms the mammary glands, ceruminous glands of the ear, ciliary 

 glands of the eyelids, and other special forms. The greater part of the 

 surface of the skin presents 



many little furrows which in- A B c D 



tersect so that they bound 

 rectangular spaces. On the 

 palms and soles the furrows 

 are parallel for considerable 

 distances, being separated 

 from one another by slender 

 ridges along the summits of 

 which the sweat glands open. 

 The ridges are most highly 

 developed over the pads of tis- 

 sue at the finger tips and in 

 the interdigital spaces at their 

 bases. Here the tactile func- 

 tion is most perfect. The 

 pads are very prominent in 

 the embryo and correspond 



with the " walking pads ' ' of carnivora. Similar structures occur on the soles. 



Corium. The corium is a layer of densely interwoven bundles of 



connective tissue extending from the epidermis to the fatty, areolar sub- 



I Depressions which 

 were occupied by 

 papillae. 



Ridge corresponding to 

 .> a furrow of the (jprium. 



Papillae 

 of A. 



Tactile 

 corpuscle. 



Papillae 

 of D. 



FIG. 360. VERTICAL SECTION FROM THE^SOLE OP THE 

 FOOT OF AN ADULT. SHOWING FOUR RIDGES (A-D) 

 WITH A PAIR OF PAPILLAE BENEATH EACH. Between 

 the papillae of D is the duct of a sweat gland. i_Xizs . 



Portion of the duct of 

 a sweat gland. 



FIG. 361. EPIDERMIS FROM THE SKIN OF THE DORSUM OP THE HUMAN FOOT, SEEN 

 FROM THE LOWER SURFACE. X 120. 



cutaneous tissue (Fig. 359). Its epidermal surface exhibits papillae which 

 are tallest and most numerous on the palms and soles. Their height may 

 be 0.2 mm. In the skin of the face they are poorly developed and in old 



