cnAP. xxxiii.] PHYSICAL GEOGRAPHr. 437 



sunk down, we must suppose the land that now constitat(33 

 Ani to have remained nearly stationaiy, a not very impro- 

 bable supposition, when we consider the gi'eat extent of 

 the shallow sea,, and the very small amount of depression 

 the land need ha\'e undergone to prodace it. 



But the fact of the Arn Islantt having once been con- 

 nected with New Guinea does not rest on this evidence 

 alone. There is such a striking resemblance bet^veen the 

 productions of the two countries as only exists between 

 portions of a common telTito^)^ I coUeck'd one hundi-ed 

 species of land-birds in the Aru Islands, and about eighty 

 of them have been found on the mainland of New Guinea 

 Among these are the great wingless cassowaiy, two species 

 of heavy brush turkeys, and two of short winged thrushes, 

 which could certainly not have passed over the loU miles 

 of open sea to the coast of New Guinea. This barrier is 

 equally eftectual in the case of many other birds which 

 live only in the depths of the forest, as tlie kinghuuters 

 (Dacelo gaudicbandi), the fly-catching wrens (Todopsis), 

 the great crown pigeon (Goura coronata), and the small 

 wood doves (I'tilonopus perlatus, P. aurautiifrons, and P. 

 coronulatus). Now, to show tlie real effect of such a 

 barrier, let us take the island of Ceram, which is exactly 

 the same distance from New Guinea, but separated from it 

 by a deep sea. Out of about seventy land-birds iidiabiting 

 Ceram, only fifteen are found in New Guinea, and none 

 of these are terrestrial or forest-haunting species. The 

 cassowary is distinct ; the kingfishers, parrots, pigeons, iiy- 

 catchers, honey suckers, tbnishes, and cuckoos, are almost 

 always quite distinct species. More than this, at least 

 twenty genera, which are common to New Guinea and 

 Aru, do not extend into Ceram, indicating with a force 

 which every naturalist will appreciate, that the two latter 

 countries have received their faunas in a radically diflei-ent 

 manner. Again, a true kangaroo is found in Aru, and the 

 same species occurti in Mysol, which is equally Papuan in 

 its productions, while either the same, or one closely allied 

 to it, inhabits New Guinea ; but no such animal is ibund 

 in Ceram, which is only sixty miles from Mysol, Another 

 small mai^upial animal (Pentmeles doreyanns) is common 

 to Aru and New Guinea. The insects show exactly the 



