
520 THE AMERICAN NATURALIST. [VoL. XXXVI. 
SKELETON. 
The ulnar, radial, and carpal bones are practically the same 
in number, relative size, shape, proportion, etc., in the normal 
and abnormal manus. There are in the polydactyle paw six 
metacarpals, a pollex of two phalanges, and five 
digits, each with three phalanges. All the bones 
of the normal paw (Fig. 17) are larger and stouter - 
than those of the polydactyle paw (Fig. 18) 
Bones of a normal paw were prepared for the 
ES? purpose of making comparisons with the abnor- 
mal skeleton in respect to weight, relative pro- 
portions, etc. In making these comparisons, 
allowances are made for the general differences 
mentioned above. 
The radial sesamoid of the carpus of the six- 
toed cat (ses., Fig. 18) is fused to the radial side 
of the scapho-lunar 
(scph-lun.) and furnishes 
the place of articulation 
for the metacarpal of the 
pollex. In the polydac- 
tyle manus the four 
external metacarpals 
(mt carp.) have the same 
articulations with the 
distal row of carpals as 
in the normal manus. In 
the normal manus the 
Fic. 15. — Palmar ured of right manus of normal cat. Pp ollex articulates with 
n.m., median nerve; z.u/n.d., dorsal ot una the trapezium (trz.) 
nerve; sz.uln.v., ventral ban of ulnar n E A 
Wii. 5. Palmar aspect of Hight manta of pei xm a, While in the abnormal 
| manus (Fig. 18) the 
metacarpal of digit B eee with the trapezium. Metacarpal 
of digit 4 (Fig. 1 18) arti ly stated, with the radial 
sesamoid (ses.), sh i is fused w the sapbolonar (scph-lun.). 
The metacarpal bones in both manus are similar, except that 
there is in the abnormal manus no “groove” for the radial 




Fic. 15. Fic. 16, 


