THE CORONET BONE. 



27 



form a surface which responds to that of the great metacarpus, 

 with which they are in contact. The outer surface of the 

 external sesamoid and the inner surface of the internal are 

 very rough, and show marked depressions for the insertion of 

 ligaments. The two remaining surfaces of the bones (fig. 13, c) 

 are convex and smooth ; in front they are in contact, posteriorly 

 they recede more and more from each other, and when in 

 position form a groove filled with cartilage in the living animal, 

 over which the flexor tendons play. 



The upper end or apex is pointed and formed by the con- 

 vergence of all three surfaces. The lower end or base is 

 rounded off. 



4. The Cokonet Bone or Second Phalanx 

 (Figs. 10 and 11, D\ Figs. 14 and 15) 



Lies below the suffraginis but above the pedal and navicular 

 bones. It is approximately one-half the size of the suffraginis. 

 In form it resembles a cube, slightly compressed from before to 



Fig. 14.— Antero-lateral viewof coronet 

 bone. «, upper articular surface ; b, 

 anterior surface ; c, lateral surface ; 

 d, lower articular surface. 



Fig. 15. — Posterit>r view of coronet 

 bone, a, smooth facet, over which 

 the flexor pedis peiforans tendon 

 glides: h, lower articular surface. 



behind. It, therefore, presents six surfaces. The upper and 

 lower are for articulation ; the upper shows two lateral depres- 

 sions and a very slight central prominence ; the lower (figs. 14 

 and 15, h) in this respect resembling the lower end of the 

 suffraginis bone, two lateral prominences and a central depres- 

 sion. The anterior edge of the upper articular surface exhibits 

 a broad, low projection. Towards the sides this edge is 

 sharp, behind strong and rounded : powerful ligaments are 

 attached to it. Behind is a smooth area (fig. 15, «), wdiich 

 serves as a gliding surface for the flexor pedis perforans tendon. 

 The anterior and posterior surfaces (figs. 14, h, and 15) are, when 



