TEE INTEGUMENTARY APPENDAGES. 



807 



Fig. 376. 



tioiis is confounded with the frog and sole ; the lower appears between these 

 two parts, and is effaced at a certain distance from the point of the frog. 



SOLE. The sole is a thick horny plate comprised between the inner bor- 

 der of the wall and its reflected prolongations ; thus occupying the inferior 

 face of the hoof. It offers two faces and two borders or circumferences. 



The inferior, or external face, forms a more or less concave surface, 

 according to circumstances. The superior, or internal face, corresponds to 

 *he peripheral portion of the velvety tissue ; it shows a multitude of little 

 ipertures analogous to those of the cutigeral cavity, into which are inserted 

 the papillsB of the keratogenous membrane. 



The external border, or large circumference, is united, throughout its 

 extent, to the inner contour of the lower border 

 of the wall, by means of its denticuhe, which 

 are reciprocally dovetailed into those on the 

 inner face of the wall near its inferior border. 

 The internal border, or small circumference, is a 

 deep, V-shaped notch, widest behind, which cor- 

 responds to the bars, and at the bottom of which 

 the point of the frog is fixed. 



FROG. This is a mass of horn, pyramidal in 

 shape, and lodged between the two re-entering 

 portions of the wall. It offers four planes (or 

 sides), a base, and a summit (or point). 



The inferior and the two lateral planes con- 

 stitute the external surface of the organ. The 

 first is hollowed by a longitudinal excavation, 

 which is shallow in well-formed hoofs, and is 



named the median lacuna of the frog, separating PLA NTAR OB GROUND SURFACE 

 the two salient portions, or branches, which di- OF A HOOF; RIGHT FOOT. 

 verge posteriorly and join the heels. The other The interval from a to a repre- 

 two planes are directed obliquely downwards and sents the toe ; From a to 

 inwards; they adhere closely, at their upper third, 

 to the external side of the bars, and anteriorly 

 to the inner border of the sole. - " This union 

 is so close that no line of demarcation is appa- 

 rent between these parts, and their separation 

 can only be obtained by prolonged maceration. 

 The non-adherent, or free portion, forms the inner 

 side of the angular cavities known as the lateral 

 lacuncB, or commissures of the frog, whose external 

 side is constituted by the inferior face of the bars." Bouley. 



The superior plane, forming the internal face of the frog, is cribbled 

 with holes like that of the sole, and is exactly moulded on the pyramidal 

 body of the plantar cushion. It also offers a triangular excavation, divided 

 posteriorly into two latter channels by a prominence directed from before 

 backwards, to which Bracy Clark gave the name of frog-stay, but which 

 M. Bouley prefers to designate the spine or ridge (ardte) of the frog. 



The base or posterior extremity of the frog, constituted by the extremities 

 of its branches, forms two rounded, flexible, and elastic eminences separated 

 from each other by the median lacuna ; they cover the angles of inflexion of 

 the wall, and are continuous at this point with the perioplic band. Bracy 

 Clark named them the glomes of the frog. 



With regard to the summit, or anterior extremity of the organ, it is a 



outside and inside quarters ; 



c, o, Commencement of bars ; 



d, d, Inflexions of wall at the 

 heels, or " buttresses ;" e, La- 

 teral lacuna ; /, /, /, Sole ; g, 

 White line; g', g', Ditto be- 

 tween the sole and bar: h, 

 Body of frog ; *, Branch of 

 frog ; k, k, Glomes, or heels of 

 frog ; I, Median lacuna. 



