CHA?, Kxxrx.] OF THE PAPUAN ISLANDS. 



577 



A very curious fact, not liitlierto sufficiently noticed, is 

 the appcaraiica of a pure if alay element in the birds of New 

 Guiuea. We find two species of Eupetes, a cmious Malayan 

 genus allied to the forked-tail water-chats ; two ol iUeippe, 

 an Indian and Malay wren-like form ; an Amchuotheru, 

 quite resembling the spider-oatclyng lioneysuckers of Ma- 

 lacca ; two species of GnicuJa, tlie Mynahs of India ; ami 

 a curioiis little black Prionochilus, a saw-billed fruit- 

 pecker, undoubtedly allied to the Jklalayan form, althouj^ili 

 perhaps a distinct genus. Now not one of these birds, or 

 anything alhed to tlieni, occui-s iu the Moluccas, or (witli 

 one exception) in Celebes or Austmlia ; and as tliey are 

 most of them biixls of short flight, it is very dillicult to 

 conceive how or when they could have crossed the space 

 of more than a thousand uiiles, which now separates them 

 from their nearest allies. Such facts point to changes 

 of land and sea on a large scale, and at a rate winch, 

 measured by the time required for a change of species, 

 must be termed rapid. By speculating on such changes 

 we may easily see how partial waves of imniigmtion may 

 have entered New Guinea, and how all trace of their 

 passage may have been oljlitemted by the subsequent dis- 

 appearance of the intervening huid. 



There is nothing that the study of geology teaches us 

 that is more certain or more impressive tlian the extreme 

 instability of the earth's surface. Ever)^whure beneath our 

 feet we find proofs that what is land has been sea, and 

 that where oceans now spread out has once been land ; 

 and that tliis change from sea to land, and from land ti» 

 sea, has taken place not once or twice only, but again and 

 again, during countless ages of past time. Now the study 

 of the distribution of animal life upon the pre-seut surface 

 of the earth, causes us to look upon this constant inter- 

 change of land and sea— this making and nnmaking of 

 continents, this elevation and thsiippearauce of islands— as 

 a potent reality, which has always and everywhere been in 

 progress, and has been the main agent in determining the 

 manner in which living things are now grouped and scat- 

 tered over the earth's surface. And when we continually 

 come uj»on such little anomalies of distribution as that 

 jiist now described, we find the only rational explanation 



