352 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



like interlocking leaves of two books. Each lamina 

 extends approximately from the upper and inner 

 margin of the hoof to its plantar border. There 

 are from five to six hundred of these laminae in each 

 foot and they all increase in width from above to 

 below. In a horizontal section of the hoof these 

 laminae appear like so many papillae (Fig. 2480). 



From such a sec- 

 tion it will be seen 

 that along the 

 sides of each lam- 

 ina there are about 

 sixty secondary 

 folds, called lamel- 

 la, by which the 

 surf ace between 

 sensitive and in- 

 sensitive laminae 



is enormOUSlv Itt- 



creased. These 

 secondary leaves 

 establish a fine se- 

 ries of longitudinal 

 grooves along the 

 lateral sides of 

 each lamina, as 

 seen in Fig. 2486. 

 The surface lining 

 of each horny fold 



consists of a single layer of cubical or low colum- 

 nar epithelial cells analogous and continuous with 

 the germinal layer of the skin. The cells are rich 



Horn tubes, epi- 

 thelial cells. 



Horn matrix, epi- 

 thelial cells. 



Insensitive lamina, 

 epithelial tissue. 



Secondary lamina or 

 lamella lined by 

 malpighian layer of 

 epithelial cells. 



Sensitive lamina con- 

 nective tissue. 



Blood-vessel. 



Fig. 2480. Horizontal section of hoof of 

 horse. 



