354 JAMES ROLLIN SLONAKER 
and 2 mm. wide. Its proximal end is attached to the pollex or 
flexor side of the distal end of the radius. From its attachment 
it curves outward and in the direction of the palm and along the 
side of it to end on the flexor side of the manus near the level of 
the proximal end of the second phalanx of the pollex. It thus 
not only adds to the width of the manus, but also serves to add 
firmness to this margin of the hand. 
The metacarpal bones and the phalanges are of the usual 
number, but very much reduced in length. The terminal pha- 
langes are bifid at their distal extremity. This has been de- 
scribed by other investigators in other species of moles and also 
in the scaly anteater, Manis, by Humphry (’70). Mivart (’71) 
says that these bifurcations are less pronounced in Scalops 
aquaticus than in Talpa. In figure 13 the terminal phalanx of 
the third digit is shown in outline as seen through the intact nail. 
The manus in Scalops is thus broad and spade-like in shape 
and armed with strong flat nails which practically inclose the 
terminal phalanges. ‘The palm is much broader than long. It 
is 17 mm. wide and 11.3mm. long. The toes, being fully webbed, 
make is a very effective organ for digging. In Scapanus and 
Parascalops the palms are as long as broad and the toes are not 
webbed, but provided with broad flat claws. In Condylura the 
palms are as long as broad, the toes not webbed and relatively 
long and armed with rather long and somewhat narrowed claws. 
In Neiirotrichus the manus is less hand-like, the palms are longer 
than broad and the toes are relatively long and not webbed. It 
is not such a powerful organ for digging as in the other genera. 
Likewise, the other bones of the arm are not so strongly built as 
in those forms with the strong spade-like manus. 
The manus at rest is so placed that the palmar surface is 
directed mainly outward, but also slightly upward and back- 
ward. This brings the pollex edge, which is reinforced by the 
strong os falciforme, on the ventral edge. This edge is sub- 
jected to greater strain in the process of digging than the oppo- 
site edge, and adaptation is shown in its reinforcement. Since 
there can be little if any rotation of the hand, the movement 
at the wrist consists probably wholly of flexion and extension. 
