26 
HORN RXPRDITION—MAMMALIA. 
It is difficult, unless actually seen, to realise the different conditions of 
environment consequent in Central Australia upon good or bad seasons. In the 
latter all is dead, dry, and sterile, scarcely an insect, save ants, to be seen; in the 
former, everything is green and flourishing—flowers, insects, and animals of all 
kinds become abundant. 
We know that in the case of Crustacea, such as Estheria and Apus, and 
amongst the frogs, very rapid growth takes place, so that the animals are enabled 
to take advantage of a good season directly it comes. Possibly the same is true of 
the smaller mammals. Tliey cannot mstivate like the frogs do, but in all likelihood 
they have the power of very rapid growth if conditions be favourable, when, and 
only when, they will reach their full state of development. 
In addition to those of which the dimensions are given, I have, amongst 
others, four young ones, three females and one male. These were captured, 
together with females with young attached to the mammre, in November and 
December, which is evidently a breeding time. The four larger young ones belong 
to the pi’evious breeding season, and cannot be many months old. 
In no specimen, mature or immatui’e, is there any trace of a lowerIn the 
lower jaw thei’e is a slight and in the upper (when p'^ is wanting) a larger diastema 
between and 
The only specimens in which the upper p^ can be seen are (1) specimen c, in 
which it is present, very small and tubercular in shape, on the left side only ; 
(2) specimen in which it can be just seen on each side ; (3) specimen in which 
it is present on each side as a small tubercle; (4) specimen /, in which it is present 
in the same condition ; (5) specimen ?;/, in which it is very minute and pushed out 
to the side of the jaw. 
In this species the lower p^ has evidently been completely lost; there is no 
milk upper p'^ to be seen, and the permanent tooth is evidently gradually 
disappearing, the result being a close approximation, so far as numbers are 
concerned, to the dentition which is characteristic of the genus Dasyurus. 
There is also considerable variation in the size of tlie hallux, which in 
specimen p is very small. 
Note. —Since the above was written I have received additional specimens 
through the kindness of Messrs. Gillen and Byrne. In each of foiir lai-ge females 
eight mammce are present, and young have evident/y been attached to all of them. 
In another somewhat smaller specimen seven mamma? are present, four on the left 
