83 



perforated by vessels : there is no trace of an articular surface for the 

 cuboides on the outer margin, or for a middle cuneiform bone on the 

 inner one. The single articular surface for a cuneiform bone to the 

 inner side of the preceding is separated by a non-articular surface of two 

 lines in breadth, indicating that there was only one cuneiform bone and 

 one toe on the inner side of the outer cuneiform bone and third toe. 



448. The proximal phalanx of the innermost toe, which corresponds to the 



second toe in the pentadactyle foot of ordinary mammals. 



The second phalanx, though small, is larger in proportion to its breadth 

 than in the great adjoining toe : it is slightly compressed, with the 

 proximal surface moderately and uniformly concave, of a vertically oval 

 form, turned slightly inwards, and with the larger end terminating below 

 in two tubercles : beyond these the phalanx suddenly diminishes in 

 vertical thickness : the sides of the shaft are convex, the under part 

 slightly concave : the distal articulation is a pulley of three surfaces ; 

 the middle one concave, the two lateral strongly convex : the vertical 

 extent of this trochlea is less than half that of the proximal articulation. 



449. The middle phalanx of the adjoining toe, which corresponds with the 



third or middle toe in the pentadactyle foot. 



The proportions of this phalanx differ much from those of the 

 preceding bone ; its antero-posterior diameter exceeds by one-eighth 

 part the vertical diameter, and by one-third part the transverse diameter. 

 The depth of the phalanx rapidly contracts from the proximal end ; the 

 sides are flattened, and slightly concave in the middle : they terminate 

 anteriorly in the convex borders of the distal trochlea, which describe 

 two-thirds of a circle ; the medium depression of the pulley follows the 

 same curve, and terminates both above and below in a wide and deep 

 cavity. The proximal articulation consists of two vertical concavities 

 separated by a median ridge, the upper extremity of which is more 

 produced than the lower one ; but both combine to restrict the move- 

 ments of the middle upon the proximal phalanx in the vertical direction, 

 in which alone any motion is permitted by the form of the articular 

 pulley. 



m 2 



