12 The Mammalian Fauna of the Australian Desert. [January, 
Bettongia grayi, Gray's jerboa or the sandhill wallaby, is found 
among the sandhills, and is solitary in habit. I never saw two of 
them together. It is very swift and dexterous, dodging in and out 
among the bushes in a surprising manner. 
Among the Peramelide we find Perameles fasciatus and Pera- 
galea lagotis, known respectively as the banded and the long-eared 
bandicoot. Both of them are found in the sandhill country. 
Chæropus castanopus is also found, but it is rare. 
Along the creeks, and especially where there are abundant 3 
water holes, phalangers (Phalangista) are abundant, but of whati 
species Iam uncertain. 
The above are all the mammals that I met during my two 
years’ sojourn. When the country is better known more will 
probably be found. The number of forms depends greatly on 
the character of the season. After a rain animals visit the desert 
that are not known there at other times. Hence the conflicting 
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A 
reports received so often on the subject. With the exception of 
col ly eedt poh Se ie a ose acl EEEE N a aA 
Osphranter rufus those mentioned above are true desert forms; — 
that is, they are always found there. It is worthy of note that the 
; 
Marsupialia, though furnishing the greatest number of species, are 4 
not the predominating order of mammals. The Rodentia pre- _ 
ponderate in number and almost equal the former in species. A 
This is a notable exception to the other parts of the continent. it 
is still more interesting to notice that two' (the jerboas) of the 
four species of Rodentia remarkably resemble certain forms of the — 
Marsupialia. Like physical conditions seem to tend to produce — 
similar forms out of different types of animals. In other parts of 
the continent certain marsupials have developed into carnivores 
curiously resembling some forms among monodelphian Carnivora. 
The mammals living at present in the desert are small, and are 
well adapted to the life they lead. When contrasted with the 
giant marsupials which once inhabited the region, and whose 
remains we now find here and there in it, we can see how much 
the character of the fauna depends on the constancy of the physi- 
cal conditions of the region. Slight changes produce great 
results. 
