432 



Messrs. A. and E. Newton on the [June 11, 



the cause of the error (if such it be) may he ascribed, without derogating 

 from his truthfuhiess, to his anxiety to point a moral, which may have led 

 him to imagine he saw what he wished to see. He especially mentions that 

 one sex would not fight with the other, which is just what takes place among 

 polygamous birds. The case of a very well-known bird (^Otis tarda), 

 about which much has been written, is then cited, to show that even now, 

 after centuries of observation, it is doubtful whether it be monogamous or 

 polygamous. Leguat, therefore, may easily have been mistaken in his 

 opinion, even setting aside his evident leaning on the matter. The notion 

 of Pesophaps having been polygamous was before entertained by one of the 

 authors, and arises from a consideration of the great difference in the size 

 of the two sexes, which in birds is generally accompanied by polygamous 

 habits ; but the question is now not likely to be solved. 



The amount of variability which every bone of the skeleton of this species 

 presents, warrants the conclusion that as much was displayed in those 

 parts of its structure which have perished, letting alone Leguat' s direct 

 evidence as to the individual difference in the plumage of the females. If 

 such a process, therefore, as has been termed Natural Selection," or 



Survival of the Fittest," exists, there would have been abundant room 

 for it to operate ; and there having been only one species of Pesophaps 

 might, at first sight, seem an argument against the belief in such a process. 

 A little reflection, however, will show that such an argument is unsound. 

 Confined in a space so restricted as one small island, every individual of 

 the species must have been subject to conditions essentially identical in all 

 cases. Whatever power such a process might possess, there would be 

 neither occasion nor opportunity for its operation, so long as no change took 

 place in the physical character of the island. But if we venture to indulge 

 our fancy, and consider what would have been the inevitable result of a 

 gradual upheaval of the island, and a corresponding extension of its area 

 until it became vastly increased and its original low rounded hills were 

 exalted into mountains, it is plain that a great variety of physical con- 

 ditions would be thereby incurred. One side of the island Avould be ex- 

 posed to the full force and direct influence of the trade- winds, the other side 

 would be completely sheltered from them. The climate of these two por- 

 tions would accordingly differ, and a great difference would be speedily 

 wrought in the character of their vegetation, while that of the elevated 

 central part would undergo a corresponding modification. After some longer 

 or shorter period, we can conceive the island itself being broken up into two 

 portions, separated from one another by a strait, such as divides the North 

 and Middle Islands of New Zealand. This rupture would certainly tend 

 still more to affect the existing fauna and flora ; and at the end of another 

 epoch there can be little doubt but the animals and plants of each portion, 

 exposed to different influences, would present a decidedly different appear- 

 ance, and the eastern and western islands (supposing the separation to 

 have taken place in the direction of the meridian) might each possess its 



