274 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
has become enlarged to correspond with the increased size of its digit 
(11); it articulates chiefly with metacarpal 1, its facet for 11 being 
small. The radial process of metacarpal mm is considerably reduced. 
In another case (Plate 7, Fig. 15) the trapezium was fused to the 
proximal end of metacarpal 1. 
In Figure 16’ (Plate 8) is shown a manus which exhibits an extremely 
interesting structure. The extra digit is identical in its structure with 
that of the manus figured in Plate 6, but the second digit is very 
strongly developed, and is in fact more massive than either 11 or Iv. 
tre. trad. os mag. wn. 
‘ { 4 
II. III. IV. 
Fic. N.— Anterior view of left polydactyle manus of the pig, showing lower row of 
carpals and metacarpals. I-v, metacarpals; os mag., os magnum; ¢rz., trapezium; trzd., 
trapezoid; wn., unciform. # natural size. 
Its hoof is large, convex on its radial, and flat on its ulnar surface ; it 1s 
entirely independent of the hoof of digit m1. The third phalanx of 
digit 1m is also convex on its radial side; that of digit 1m is indifferent, 
and its hoof is flat on either side. The other digits are apparently 
normal. Of the carpals, the trapezium (Fig. J, ¢rz.) is large and artic- 
ulates with the scaphoid, trapezoid, and metacarpal 1. The trapezoid 
(tred.) is nearly as large as the os magnum (0s mag.), and its single 
distal facet articulates with only metacarpal 11. 
Of the metacarpals, 1 is small but well formed ; 11 is larger than 111 
at its distal end and shows evidence there of pathological hypertrophy. 
