406 The Bell-birds of America. 



angles of its mouth. These are thinner and narrower than the 

 Araponga's single horn, and attain a greater length — the 

 medial caruncle in a young male bird in my collection measur- 

 ing nearly 4^ inches in length, and extending, when recum- 

 bent, down beyond the middle of its back. The female of the 

 Costa- Ei can Bell-bird again hardly differs materially from the 

 females of the other species." * 



It appears, therefore, that there are four rather widely 

 separated districts in tropical America, each of which is 

 tenanted by a distinct species of this group of birds. The in- 

 telligent mind naturally proceeds to inquire why this is so. 

 Why should the Bell-bird of Brazil be different from the Bell- 

 bird of Cayenne, and the Bell-bird of Venezuela from that of 

 Costa Bica ? What is the meaning r of these four birds, each 

 having a special abode into which the others never intrude ? 

 Why are the males of each of them all so different, and the 

 females all four so much alike ? Not many years ago it would 

 have been thought rather irreverent to ask such questions as 

 these. We should have been informed in reply, that it was 

 for the same reason that " dogs delight to bark and bite" — ■ 

 because Divine Providence ' ' hath made them so ;" and it 

 would be, therefore, no use inquiring into the matter. And 

 this is the theory (if theory it can be called) of the supporters 

 of " special creation" to the present day. They say that each 

 species of organic beings was created to perform certain func- 

 tions over s, definite area, and there is an end of the matter. 

 But it is not easy to satisfy the inquiring spirit of the present 

 age in so summary a manner. Let us try, therefore, if by 

 adopting Mr. Darwin's views of the derivative origin of species 

 and (C natural selection," we can invent a theory of any sort 

 which would account for the present state of things as regards 

 the case of these four Bell-birds, and numerous other cases of 

 the same description. 



Let us suppose then, that these four Bell-birds, now so dis- 

 tinct, are all descended from a common progenitor — a certain 

 " GJtasrnorhynchus priscus" we will call him.' This would at 

 once account for the females of the four species being all alike. 

 Let us suppose that in bygone ages Gkasmorht/nchus priscus 

 lived in a small area (a, b, c, d, Fig. 1) occupying the centre of 

 the extended area A, B, C, D. Let A, B, C, D represent the 

 ''generic area" of Ghasmorhynclms at the present period, that is 

 the whole of the areas now occupied by the four known species of 

 the genus, together with the intervals between them which 

 are not now tenanted by any species of Ghasmorhynchus. 



* Both sexes of this very singular bird are figured in the Ibis for 1865, PI. 

 iii., where Mr. Salvin has likewise given many interesting remarks on this and the 

 allied forms. 



