No. 403.] REVIEWS OF RECENT LITERATURE. 595 
Hedley maintains that the faunas of Australia and the Pacific 
Islands — generally united into the Australian region — have devel- 
oped under two completely different conditions. On the one side, the 
western, continental conditions prevailed, Australia proper being 
connected with New Guinea, and New Guinea, in turn, through the 
Solomon Islands, New Hebrides, and New Caledonia, with New 
Zealand, while the Fiji Islands formed another branch of this old 
continental mass, being connected with the New Hebrides and 
Solomon Islands. 
On the other side, the eastern, we have the rest of the Pacific 
Islands, where oceanic conditions have always prevailed, the different 
islands of the Gilbert, Ellice, Samoan, Tonga groups, etc., never 
forming a continuous continent. 
This fundamental difference finds its expression in the faunas of 
these two parts, in so far as in the western part a “ harmonic " fauna 
(G. Baur) exists, that is to say, a fauna that is composed of the chief 
groups of animal life, without considerable gaps. In the eastern 
part, however, such gaps are very frequent and mark the fauna at 
once as a *disharmonic," many important groups of animals being 
completely missing. In the western part a continuous migration 
over the whole extent of this continental mass was possible, thus 
favoring more even distribution of the land animals over the whole 
area, while in the eastern part the land fauna could only migrate by 
drift over the intervening parts of the ocean. which excludes at once 
a large number of animals.: 
In the fauna of the western, or continental, part we can distinguish 
three chief constituents: (1) an Australian-Autochthonian (Tate), 
or Éyrean (Spencer), which is restricted to Australia proper, and 
hardly passes beyond Queensland to the north; (2) the so-called 
Euronotian (Tate), or Bassian (Spencer), which is the most charac- 
teristic Australian element, and of antarctic origin ; it entered Aus- 
tralia by the south, over Tasmania, and crossed Torres Strait into New 
Guinea, reaching its limit in the Solomon Islands ; (3) the Torresian 
(Spencer) element. Its center lies in New Guinea, from whence it 
was connected with the Indo-Malaysian fauna. It sends off from 
New Guinea two branches, the one crossing Torres Strait southward 
and entering Queensland, the other one traversing New Britain, New 
Ireland, the Solomons, sending an offshoot to Fiji and another along 
the chain of the New Hebrides and New Caledonia, ultimately 
arriving at New Zealand. 
In New Zealand the southern advance of the Torresian element 
