372 



may I request the favour of your opinion on these bones, and also the 

 information whether any others of similar character have been found 

 elsewhere ? 



" I beg to remain, dear Sir, your obedient Servant, 



" William Williams." 

 " To the Rev. Br. Buck/and, fyc. fyc" 



The remarkable geographical distribution of the birds of the Stru- 

 thious order, which have no power of transporting themselves to distant 

 isles or continents, either through the air or the ocean*, irresistibly leads 

 us to speculate on the cause of that distribution, and its connexion with 

 the former extent and importance of the wingless terrestrial birds. 

 Hereupon it may first be remarked, that those species now in existence 

 which have the least restricted powers of locomotion, enjoy the most ex- 

 tensive range for their exercise. 



The Ostrich is spread over nearly the whole of Africa, from the Cape 

 to the deserts of Arabia ; beyond which the species is unknown. The 

 Rhea ranges over a great part of the southern extremity of the Western 

 hemisphere. To the Emeu has been assigned the vast mainland of 

 Australia. The heavier Cassowary is limited to a few of the islands of 

 the Indian Archipelago. The Dodo appears to have been confined to the 

 Mauritius and the small adjoining Isle of Rodriguez. The Apteryx still 

 lingers in New Zealand, where alone any specimens of that most anoma- 

 lous species of the Struthious order have been discovered. 



New Zealand was also, at one period, the seat of a seventh genus of 

 StruthionidcE ; and it is worthy of remark, that the Fauna of no other 

 island, nor of any of the great continents, has yet furnished an analogous 

 example of two distinct genera of that group of birds. Moreover, the 

 most gigantic as well as the most diminutive species of the wingless 

 group — always to Ornithologists most remarkable for the great size of 



* The Rhea and Emeu have been seen to take water for the purpose of crossing rivers and narrow 

 channels of the sea; but almost the entire body sinks below the surface, and their progress is slow, 

 as might be anticipated from the absence of the swimming-webs in their feet. See Darwin, ' Voyage 

 of the Beagle,' vol. iii. p. 105. 



