THE INTEGUMENTARY APPENDAGES. 



811 



distinct in the midst of the other cells, as in those of the wall formed by the 

 coronary cushion. 



The horn thrown out on the surface of the podophyllae, immediately 

 after the removal of a fragment of the wall, is not a definitive horn, but 

 must be replaced by that from the coronet. This substitution is complete ; 

 as a microscopal examination proves that the wall which descends from the 



Fig. 379. 



HORIZONTAL SECTION OF THE JUNCTION OF THE WALL WITH THE SOLE OF THE HOOF. 



a, Wall, with its horn-tubes ; b, b, Horny laminae projecting from the wall ; c, c, 

 Horn-tubes formed by the terminal villi of the vascular laminae, the horn 

 surrounding them and occupying the spaces between the horny laminae, con- 

 stituting the " white line ;" d t Horny sole, with its tubes. 



cushion, and is furnished with horny laminae, passes beneath the provisional 

 wall, and glides downward by the combined action already mentioned over 

 the surface of the soft cells of the vascular laminaB. As soon as the latter 

 are covered by the proper wall, their marginal papillae become atrophied, 

 and they again assume the limited function pertaining to their physiological 

 condition. 



Fig. 380. 

 c" d" d 



d" 



d' 



HORIZONTAL SECTION OF THE WALL, AND HORNY, AND VASCULAR LAMINA, TO 

 SHOW THE JUNCTION OF THE LATTER AND THE LAMINELL^. 



a, Inner portion of the wall with the laminae arising from it ; 6, Vascular laminae ; 

 c, Horny lamina of average length ; c', c', Unusually short laminae ; c", c", 

 Laminellae on the sides of the horny laminae ; c?, Vascular lamina passing between 

 two horny ditto ; d', Vascular lamina passing between three horny laminae ; d", 

 Lateral laminellae ; <?, e, Arteries of vascular laminae which have been injected. 



(The description of the disposition of the epithelial cells given by 

 Chauveau does not coincide with my own observations. As he correctly 



