290 THE ARU ISLANDS. [chap, xxxni. 



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

 nected with New Guinea does not rest on this evidence 

 alone. There is such a striking resemblance between the 

 productions of the tAvo 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 mainland of New Guinea. 

 Among these are the great wingless cassowary, two species 

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

 which could certainly 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, wliich is exactly 

 the same distance from New Guinea, but separated from it 

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

 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 

 always quite distinct species. More than this, at least 

 twenty genera, which are common to New Guinea and 



