ANTERIOR EXTREMITY. 41 



The metacarpal bone of the second finger is smaller at its proximal 

 extremity, where it is connected with the carpus, than at its distal, where 

 connected with the phalanx. Its length is five inches. It is articulated 

 superiorly with the trapezoides and os magnum, internally with the middle 

 metacarpal, inferiorly by an arched articulation with the first digital phalanx. 



The metacarpal bone of the median or third finger is the largest, 

 measuring six inches and a half in length, narrower at its proximal than 

 at its distal extremity. The superior surface is comparatively smooth ; 

 the inferior, excavated, presents a great tuberosity, which is possessed in 

 common by it and the two adjoining metacarpals ; all of which are con- 

 nected with the sesamoids, and serve with them to support the weight of 

 the auimal. It is articulated, by its proximal extremity, with the os mag- 

 num and unciforme ; by its distal, with the first phalanx. 



The -metacarpal bone of the fourth finger is shorter, being five inches 

 long; and, like the last, is narrower at the proximal than at the distal 

 extremity. It is articulated with the unciforme and first phalanx. 



The metacarpal bone of the fifth finger is quite large and irregular; 

 the outer edge is prominent, long, and rough ; the inner edge is shorter 

 and rougher; the superior surface is irregular, and indented at its lower 

 part. The bone has a wedge-like form, the sharp part looking down- 

 wards. 



Phalanges. — The phalanges of the thumb are two in number. The Phalanges. 

 first phalanx is of an irregular form, larger at its metacarpal than at its 

 phalangeal extremity. It is excavated on its superior surface, as if bent 

 upwards ; its anterior extremity presents a convex articular pulley for the 

 second phalanx. The principal support to the body of the animal in this 

 finger is the inferior posterior extremity of the first phalanx. The bone is 



