GREGOEY — ON CiENOLESTES 
111 
most nearly met in certain of the dasyures, and that although the 
short colon is perhaps primitive, the small caecum is obviously a second- 
ary condition. 
In brief, to judge from its nutritional habitus as a whole, one might 
infer (as Doctor Osgood does) that Ccenolestes is a descendant of that 
part of the primitive polyprotodont group which gave rise both to the 
Peramelidae and to the Australian diprotodonts. 
III. HABITUS AND HERITAGE OF THE LOCOMOTOR APPARATUS 
A. Habitus 
The locomotor habitus involves primarily the locomotor system of 
nerves, muscles, connective tissue, ligaments, axial and appendicular 
skeleton. It is supported of course by the activities of the food habitus 
and is controlled by the nervous system. It subserves the needs of the 
protective, nutritional and reproductive systems. 
Among other significant facts regarding the skeleton as a whole are 
the following: the head is decidedly long in proportion to the size of the 
thorax, as in insectivores, and in contrast with most ungulates, in which 
the head is comparatively small. The thorax is relatively small, 
perhaps because the food is highly nutritious, and especially because a 
small animal needs relatively far less food than a large one. The 
locomotor skeleton must therefore be adapted to the support and pro- 
pulsion of a large head and a relatively light thorax. Accordingly we 
find that the backbone has the cervical vertebrse quite short, with a 
very large lumen for the spinal cord, that the dorsal and lumbar and 
more proximal tail vertebrae are large, as are also the chief muscles of 
the back. 
Limbs and feet. The most conspicuous and easily interpreted parts of 
the locomotor habitus are usually the extremities. In Ccenolestes the 
pes presents a general development similar to that of Phascogale in so 
far as it has a reduced clawless hallux and is rather narrow, with four 
sub-equal clawed digits. Such a foot is of the sub-cursorial rather than 
arboreal type, as indicated also in the skeleton of the foot, the astragalus, 
for instance, being somewhat intermediate between that of the pedi- 
manous marsupials and that of the highly saltatorial forms (Osgood, 
p. 95). In this connection Osgood notes (p. 60) that ^Hhe muscles of 
the legs and feet in Ccenolestes are adapted to a terrestrial, almost 
cursorial life. The leg muscles have short, thick, fleshy parts and very 
long tendinous extensions, relatively longer even than in such terrestrial 
