166 COPE. (Vo. III. 
use the nomenclature of Dr. H. Allen. In plantation, planti- 
grade mammals do not turn the toes outwards ; while digitigrade 
forms do turn them out. This may be readily observed in 
anterior and pos- 
Poe terior views of 
most of the Dip- 
x ‘- larthra in motion, 
and especially in 
Artiodactyla. In 
plantation, the el- 
bows and hocks 
rotate inwards, and 
the toes outwards. 
In recovery, this 
rotation is neces- 
sarily continued. 
As the body pass- 
es the position of 
the stationary limb 
and foot, it gives to 
the latter a slight 
twist outwards and 
forwards, in answer 
to which the foot 
is lifted from the 
ground, or recov- 
C ered. At recov- 
Figure 13.— Procyon lotor, gaits; from Muybridge, €Ty, the rotation 
Animal Motion. 4 shows semisupination of the left ¢c@yznot be in any 
manus and lever strain on right pes in recovery; 4, lever other direction in 
any mammal; in 
plantation, it say 
de forwards and inwards, or forwards and outwards. In recov- 
ery, the twist is greater in a long than in a short limb. In 
the language of mechanics, the length of the arc of torsion 
is directly as the length of the limb. It is probable that it is 
for this reason that the digitigrade forms turn the toes out in 
plantation also, the structure having adapted itself to this mo- 
tion, so as to perform antero-external rotation most easily.’ In 
strain on recovery of right manus, and plantation of left 
pes; C, plantation of left manus. 
1] have made these observations on various species of Auchenia, Camelus, An- 
tilocapra, Antilope, Capra, Bos and Cervus, and in Tapirus, Rhinocerus and Equus, 
