50 BARBOUR: ZOOGEOGRAPHY. 



of the great majority of these is limited to the Cape York Peninsula region of 

 Queensland, which undoubtedly within a short time formed an integral part of 

 Papua itself, and may indeed be considered more Papuan than Australian. 

 The rest of Australia — that part of the continent where were evolved the great 

 hordes of typical Australian forms — was probably separated from northern 

 Queensland until just before the break took place through Torres Strait. The 

 fauna of the Bismarck .Aj-chipelago, of the Louisiade Islands, and of the Solo- 

 mons is truly Papuan, and shows little affinity to that of Austraha, except inas- 

 much as some of these same Papuan forms occur which are now found to be 

 common to both New Guinea and Queensland. As would be expected, these 

 species are more common in that part of New Guinea which lies directly opposite 

 Cape York Peninsula than they are in the western, Dutch section; though 

 many of them are wide-ranging, and some reach out to those islands in the 

 Moluccas where the'Papuan element in the fauna is distinctly traceable. 



No single true Malayan species is found in this whole region, except Dibamus 

 novae-guineae, which may not be Malayan at all. A number of Malayan genera, 

 however, occur, some of these reaching to Queensland itself. 



Regarding New Guinea, again, it is only fair to say that we are hampered 

 by lack of knowledge; and nearly every year new genera, especially among the 

 inconspicuous burrowing forms, are being discovered; so that sets of figures 

 showing proportionate relationships between the different elements in the fauna 

 here may vary greatly from year to year. 



Among the Amphibia conditions are of especial interest. The family of 

 Cystignathidae, which is so characteristic of both Australia and South America, 

 and serves to emphasize the relationship between these two areas, has only 

 recently been found upon Papuan soil; while the enormous predominance of 

 engystomatids observed by van Kampen has served him as the basis of a \'ery 

 ingenious theory regarding the coming of amphibians to New Guinea from the 

 mainland of Asia. Now, we know, from recent data, that the life histories of 

 many of these engystomatid amphibians are similar to those which have long 

 been known for certain New World species, such as the classic Eleutherodactylus 

 martinicensis (Ptrs.) ; that is, they skip their larval stage, and the life cycle is 

 completed within the egg, which is placed for incubation either in soft mud, 

 damp ground, or in the little collections of moisture which are held in the axils 

 of leaves of so many tropical plants, bromeliaceous, and others. This is dis- 

 tinctly and at once evidently an adaptation to regions where only small amounts 

 of standing water are usually met with. Van Kampen maintains that the 



