144 
MARSUPIALIA 
the fourth ; the fifth somewhat shorter. 
the body, and covered with short hairs forming a slight crest. 
Fic. 43.—Skele- 
ton of right hind 
foot of Cheropus 
castanotis. c, Cal- 
caneum ; a, astra- 
galus ; cb, cuboid ; 
n, navicular ; c3, 
ectocuneiform ; IT 
and III, the con- 
joined second and 
third digits; IV, 
the large and only 
functional digit ; 
V, the rudiment- 
ary fifth digit. 
equal, stout, and short. 
Tail not quite so long as 
Ears 
large and pointed, and folded down when the animal 
is at rest. Fur soft and loose. Vertebre: C 7, D 
13, L 6,81, C 20. Skull short and wide, with a 
small and single bulla, and a contraction of the 
muzzle at the third premolar. 
The only known species of this genus (Fig. 44), 
chiefly remarkable for the singular construction of 
its limbs, is an animal about the size of a small 
Rat, found in the interior of the Australian continent. 
Its general habits and food appear to resemble those 
of the other Peramelide. It was first described as 
C. ecaudatus by Ogilby from a mutilated specimen, 
but the specific name was afterwards changed, as being 
inappropriate, by Gray to castanotis. 
Suborder DIPROTODONTIA. 
For the leading characters of this group, see 
page 132. 
Fumily PHASCOLOMYID 
Dentition: ¢ 4,72, 94,m4=24. Allthe teeth 
with persistent pulps. The incisors large, scalpriform, 
with enamel only on the front surface, as in the 
Rodentia. The molars strongly curved, forming from 
the base to the summit about a quarter of a circle, 
the concavity being directed outwards in the upper 
and inwards in the lower teeth. The first of the 
series, or premolar, appears to have no milk-prede- 
cessor, and is single-lobed; the other four composed 
of two lobes, each subtriangular in section. Limbs 
Fore feet with five distinct toes, each 
furnished with a long, strong, and slightly curved nail, the first and 
fifth considerably shorter than the other three. Hind feet with a very 
short nailless hallux, the second, third, and fourth toes partially 
united by integument, of nearly equal length, the fifth distinct 
and rather shorter ; all four provided with long and curved nails, 
In the skeleton of the foot, the second and third toes are distinctly 
more slender than the fourth, showing a slight tendency towards 
the peculiar character so marked in the next two families. Tail 
rudimentary. Stomach simple, provided with a special gland 
situated near the cardiac orifice. Caecum very short, wide, and with 
a peculiar vermiform appendage. Pouch present. The auditory 
bulla of the skull are imperfect, open behind, with their anterior 
