•490 The Aru Islands, 



small amount of depi-ession the land need have undergone to 

 produce it. 



But the fact of the Aru Islands having once been con- 

 nected with New Guinea does not rest on this evidence alone. 

 There is such a striking resemblance between the produc- 

 tions of the two countries as only exists between portions of 

 a common territory. I collected one hundred species of land- 

 birds in the Aru Islands, and about eighty of them have been 

 found on the main-land of New Guinea. Among these are 

 the great wingless cassowary, two species of heavy brush 

 turkeys, and two of short winged thrushes, which could cer- 

 tainly not have passed over the 150 miles of open sea to the 

 coast of New Guinea. This barrier is equally effectual in 

 the case of many other birds which live only in the depths 

 of the forest, as the kinghunters (Dacelo gaudichaudi), the fly- 

 catching wrens (Todopsis), the great crown pigeon (Goura 

 coronata), and the small wood doves (Ptilonopus perlatus, P. 

 aurantiifrons, and P. coronulatus). Now, to show the 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 in- 

 habiting 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, fly- 

 catchers, honeysuckers, thrushes, and cuckoos, are almost al- 

 ways quite distinct sjaecies. More than this, at least twenty 

 genera, which are common to New Guinea and Aru, do not ex- 

 tend into Ceram, indicating with a force which every natu- 

 ralist Avill appreciate, that the two latter countries have re- 

 ceived their faunas in a radically different manner. Again, a 

 true kangaroo is found in Aru, and the same species occurs 

 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 found in Ceram, which is only sixty 

 miles from Mysol. Another small marsupial animal (Pera- 

 raeles doreyanus) is common to Aru and New Guinea. The 

 insects show exactly the same results. The butterflies of 

 Aru are all either New Guinea species, or very slightly mod- 

 ified forms ; whereas those of Ceram are more distinct than 

 are the birds of the two countries. 



