DIPROTODONTIA. 747 
markedly resembles the Cape golden mole. It is thus a good 
illustration of ‘‘ convergence,” ze, the appearance of similar 
characters in forms not nearly related, apparently in indirect 
response to similar conditions of life. 
4. Family Peramelide.—The burrowing bandicoots, all small in size, 
insectivorous or omnivorous in diet. In the fore-feet two or 
three of the middle toes are well developed and clawed, the 
others being rudimentary ; in the hind-feet the hallux is small or 
absent, the second and third toes are very slender and united 
in the same fold of skin, the fourth toe is very large, the fifth 
smaller,—the whole foot suggesting that of the kangaroo. The 
‘stomach is simple; the czecum not large. Clavicles are absent 
in the adult but present in the foetus. Dentition, ae 
Examples.—The true bandicoot (Perameles), remarkable for its 
allantoic placenta; the native rabbit (Peragale lagotis); the 
rat-like Cheropus. 
B. DIPROTODONTIA 
1. Family Epanorthide.—The selvas, a family of S. American forms, 
till recently believed to be entirely extinct. The existing forms 
are included in the genus Camodestes, with two species, They 
are remarkable in having the upper jaw of the polyprotodont 
type, and the lower distinctly diprotodont ; and also in having 
all the digits of the hind-foot free, whereas in all other living 
Diprotodonts certain of these are united by skin (syndactylous). 
They are probably primitive forms, and their presence in S. 
America is highly important. There seems little doubt that 
the Diprotodonts have been evolved in the Australian area from 
a primitive widely-spread polyprotodont stock. If, therefore, the 
Epanorthidee are really allied to the Diprotodomits, their exist- 
ence in S. America seems to indicate a former connection 
between that continent and Australia. 
2. Family Phascolomyide.—The wombats, terrestrial, vegetarian, 
nocturnal Marsupials, somewhat bear-like in appearance. The 
dentition is rodent-like, we the teeth have persistent pulps, the 
incisors are chisel-edged, there being no enamel except in front. 
In the embryo, however, there are four upper incisors, of which 
the first persists, and five lower incisors, of which the third 
persists. The fore-feet have five distinct toes, with strong nails ; 
the hind-feet have a small nailless hallux, the second, third, and 
fourth toes partly united by skin, the fifth distinct. The tail is 
very short. The stomach is simple ; the czecum very short. 
There is but one living genus—Phascolomys, with three 
species. 
3. Family Phalangeridee.—Small woolly arboreal nocturnal Marsupials, 
with vegetarian or mixed diet. The fore-feet have five distinct 
toes ; the hind-feet have a large, nailless, opposable hallux, the 
