174 ON THE GEOGRAPHICAL DISTRIBUTION OF BIRDS. 



fact a variety of surprising instances were detailed. It was on this principle, he 

 Btated, that colonies are sometimes formed, the posterity of an accidentally 

 straggling pair remaining in or regularly returning to a neighbourhood, occasionally 

 insulated, and remote from other haunts of the species ; an exemplification of 

 which he adduced from personal observation, and suggested that the limited and 

 peculiar range of the Pied Flycatcher in England was in all probability thus 

 explicable. He considered that the operation of the mysterious and remarkable 

 instinct, which he had been dilating on, had been a great deal too much over- 

 looked by those who have written on the subject of the dispersion of animals ; 

 although decidedly the most .influential of the many causes which tend to 

 circumscribe their geographical range. Mr. Blyth was heard throughout his 

 discourse with the greatest attention, and received considerable applause at its 

 termination. 



N. A. Vigors, Esq., M.P., then rose, and having stated that he hoped this 

 highly interesting and important subject would be followed into its subdivisions at 

 ensuing meetings of the Society, proceeded to make a few remarks upon some 

 of its more striking points — such as the correspondency, or geographical representa- 

 tion, of groups and of species inhabiting different localities ; as, for example, the 

 Ostrich, of the African deserts, which is represented in Asia and its islands by the 

 Cassowary, in Australia by the Emeu, in the Pampas of South America by the 

 Rhea, and in Europe, as he conceived, by the Great Bustard. It was his opinion, 

 that every prominent group has thus an analogue, or representative, in each of 

 the principal divisions of the world ; or that, if in any case such representative 

 be wanting, the deficiency is invariably occasioned by some adequate and equally 

 harmonious cause. As an example, the Starling family was represented as inhabit- 

 ing all parts of the world except Australia ; the explanation of which exception 

 is, that they seek their food principally on the backs of cattle, and in Australia 

 there are no indigenous ruminant quadrupeds. It was thus that, in numerous 

 instances, the diffusion of animals is regulated by that of their prey — this, again, 

 by that of particular vegetables, which, in its turn, is dependent on the soil.— 

 Before Mr. Vigors concluded, he expressed a hope that, at the next meeting, 

 there would be laid on the table a greater number of specimens to illustrate the 

 subject of discussion. 



Mr. Chester stated, that if the gentlemen who proposed to favour the Society 

 with any scientific observations at future meetings, would apprise the Council of 

 the specimens which would be desirable for illustration, every possible exertion 

 should be used to obtain them. 



