220 
MACROPODIDjE. 
South Australia. From the same quarter the British 
Museum collection has received the skull and foot of a Rat- 
Kangaroo, the former of which is represented on Plate 6, 
fig. i. This skull, as will be seen upon comparing the figure 
alluded to with the skull, figure 3, on the same plate, greatly 
resembles that of H. penicillatus, but differs in being consi¬ 
derably smaller, and in having the nasal bones shorter: the 
palate moreover, is rather more deeply emarginated behind, 
and the hindermost molar of each series is proportionately 
smaller, being about half a line only in diameter. The foot 
which was sent with it, as appertaining to the same animal, 
resembles that of H. penicillatus, but is more slender, and 
the claws, or nails, are narrower. As the permanent premolar 
and all the true molars are fully developed, the animal must 
have been adult, and there would seem to be some grounds 
for the belief that there exists in South Australia a species of 
Rat Kangaroo, nearly allied to, but distinct from the H.peni¬ 
cillatus; the general resemblance which exists, however, 
between the two skulls, figs. 1 and 3. Plate C, is such, that I 
am rather inclined to believe that the smaller one belonged 
to an individual of II. penicillatus, which from some cause 
was stunted in its growth. Following are the dimensions 
of the small skull. 
Total length of skuU ... . 
Inches. 
2 
Lines. 
G4 
Width of ditto 
... 1 
5! 
Length of nasal bones 
11 
Width of ditto at the base 
0 
44 of ditto near the apex 
2 ? 
Length of frontal bones 
... 1 
0 
W'idth of interorbital space 
‘i 
Length of palate . 
11 
44 of auditory bulla: 
6 
44 of three incisors of upper jaw 
3 * 
41 between incisors and canine 
H 
44 between canine and carnassier 
31 
41 of carnassier 
3 
“ of ditto, and four molars, taken together 
8 } 
