North-Western Australia seems to be peculiarly prolific in birds, reptiles, and insects, who dwell here nearly unmolested, mutually preying upon each other, and thus, by a wise provision, setting the necessary check to their own multiplication. DISTRIBUTION OF ANIMALS. Of quadrupeds there are but few species, and of these the individuals, considered in proportion to the surface they roam over, are rare. The only species I observed during a residence of five months were four of kangaroos, namely the large Macropus giganteus ? of Shaw, two smaller kinds, one of which is the Petrogale brachyotis of Gould, and a kangaroo rat, which last is always seen amongst the rocks on the sea coast. One species of opossum, a flying squirrel (Petaurista) two kinds of dog, of which one is new, rats, and a fieldmouse. Of these the kangaroos are alone numerous, and only in particular spots. NEW KANGAROO. I shot a female kangaroo of the Petrogale brachyotis near Hanover Bay, and by the preservation of the skin and other parts enabled Mr. Gould to identify it as a new species. This graceful little animal is excessively wild and shy in its habits, frequenting, in the daytime, the highest and most inaccessible rocks, and only descending into the valleys to feed early in the morning and late in the evening. When disturbed in the daytime amongst the roughest and most precipitous rocks, it bounds along from one to the other with the greatest apparent facility, and is so watchful and wary in its habits that it is by no means easy to get a shot at it. One very surprising thing is, how it can support the temperature to which it is exposed in the situations it always frequents amongst the burning sandstone rocks, the mercury there during the heat of the day being frequently at 136 degrees. I have never seen these animals in the plains or lowlands, and believe that they frequent mountains alone. NEW DOMESTIC DOG.