Bibliographical Notices. 55 



beings to similar external conditions, — some would admit the sup- 

 posed order of the appearance of organic beings (as has been sug- 

 gested) on the surface of the earth, as aids or bases of classification ; 

 — the result would be, that no two naturalists would agree in the 

 same conclusion, and our system, instead of becoming a solid and 

 simple edifice, would be a labyrinth of blind passages. 



An admirable feature in Mr. Waterhouse's work is the great at- 

 tention paid to Geographical distribution, that noble subject of which 

 we as yet but dimly see the full bearing. The following remarks 

 (p. 537) give us an excellent summary on the distribution of the 

 Mammalia on the Australian continent : — 



" Australia may be conveniently divided into five principal divi- 

 sions or districts, of which the east, west, north and south portions 

 of the main land will each form one province, and Van Diemen'a 

 Land the fifth. Of these provinces, the northern one has the great- 

 est number of species peculiar to it, since out of ten species dis- 

 covered in that part of Australia, eight are not found elsewhere. 

 The Marsupiata of the eastern district are for the most part distinct 

 from those of the opposite side of the continent, there being but 

 eight species, out of upwards of sixty inhabiting the two provinces, 

 which are found in both. But if the three districts mentioned are 

 characterized by the few species which they have in common, South 

 Australia must be characterized by an opposite quality, that of having 

 a comparatively large proportion of species identical with those of 

 other districts ; indeed I know of but four species which are peculiar 

 to this district : it possesses sixteen species in common with Western 

 Australia, and fifteen in common with Eastern Australia. Western 

 Australia possesses one genus (Tarsipes) which is peculiar to it, and 

 one sub-genus (Macrotis); none of the other districts of continental 

 Australia possess any genera which are not found elsewhere. About 

 half of the species found in Van Diemen's Land are peculiar to that 

 island — in fact, nine out of twenty : of the remainder, the greater 

 portion are found on the eastern part of the main land. This island, 

 moreover, possesses one genus {Thylacinus) and one sub-genus {Sar- 

 cophilus) which are now peculiar to it. Examples of both these 

 sections have, however, been found in a fossil state on the main 

 land." 



Speaking strictly we have here four divisions, for South Australia 

 does not appear from these remarks, zoologically considered, to de- 

 serve to be ranked as a subdivision. New Guinea, however, and 

 the adjacent islands form a well-marked fifth subdivision, and an 

 interesting table is given (at p. 3) of the ranges of the quadrupeds 

 inhabiting them. The fact of South Australia possessing only few 

 peculiar species, it having apparently been colonized from the eastern 

 and western coasts, is very interesting ; for we believe that Mr. Ro- 

 bert Brown has shown that nearly the same remark is applicable to 

 the plants ; and Mr. Gould finds that most of the birds from these 

 opposite shores, though closely allied, are distinct. Considering 

 these facts, together with the presence in South Australia of up- 

 raised modern tertiary deposits and of extinct volcanos, it seems 



