Kelly — On a Case of Polydadylism. 541 



The metacarpus consisted of six bones : — 



I. Two facets on base for trapezium and second metacarpal ; head, 

 Tound and articular. 



II. Two facets on base for trapezium and first metacarpal ; the head 

 expanded and indicating a tendency to subdivision ; one large facet 

 for both phalanges. 



III. Deficient in its normal characters as second metacarpal bone ; 

 :five facets on base, the additional one for the anterior trapezoid. 



lY., v., VI., normal, or rather corresponding to the third, fourth, 

 and fifth metacarpals. 



Phalanges : — That on first poUex, and the terminal on second poUex, 

 «nded in a spine, and bore no nails ; nails were developed on all the 

 other fingers. 



The Bones of the Left Hand : — I shall only allude to those which 

 ■differ from the corresponding bones of the right hand, as both members 

 presented the same general peculiarities. 



The scaphoid : — Very large. It seemed to have attached to it the 

 portion which was in excess in the trapezoid of the right hand, and 

 here also a constriction indicated the fusion of two bones. This dis- 

 puted portion, or complemental process, in the right hand, was attached 

 to the scaphoid by a very strong interosseous ligament. 



The trapezoid : — Comparatively small. 



The OS triquetrum : — In two segments, the upper and lower, the 

 latter resembling the unciform process in size, position, and attach- 

 ments. It was bound to the unciform bone and to the upper segment 

 Tay strong ligaments ; no indication of a synovial articulation. In every 

 other respect the bone resembled that in the right hand. 



The metacarpus : — 



I. Instead of having a head with an articular facet, as on the right 

 side, ended in a spine which was capped by a cartilaginous ferule ; 

 a rudimentary phalanx, which was separated by a synovial cavity, and 

 gave attachment to some of the muscles. 



II. Base articulated with first and third, as well as with the tra- 

 pezium. The head articulated with only one phalanx. 



All the digits except the first poUex bore nails. 



III. As before mentioned, the base articulated with that of II., 

 an abnormality which did not occur in the right hand, and of much 

 anatomical interest. 



Phalanges : — First phalanx of third pollex was rounded off at its 

 proximal end, and attached by a dense fibrous cord to the side of the 

 metacarpo-phalangeal ai'ticulation of pollex two, where there was a 

 normally placed sesamoid bone on the inner side. Another sesamoid 

 bone was in the fibrous cord. 



The second and third phalanges of the same pollex (three) were 

 united, but their original separation was indicated by a node, and by 

 the difference in the direction of their axes. 



The Muscles of the Right Hand : Anterior Surface : — Flexor carpi 



3 H 2 



