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quity) and perhaps even to the elevation of the continuous land which forms the base of the mountains. It was, no doubt, during their slow elevation and the consequent loosening of the surface, that the vast masses of debris were carried down which filled up the sea separating the Andean chain from the great islands of Brazil and Guiana, and formed that enormous extent of fertile lowland forest, which has created a great continent; given space for the free interaction of the distinct faunas which here met together, and thus greatly assisted in the marvellous development of animal and vegetable life, which no other continent can match. But this development, and the fusion of the various faunas into one homogeneous assemblage must have been a work of time; and it is probable that most of the existing continent was dry land before the Andes had acquired their present altitude. The blending of the originally distinct sub-faunas has been no doubt assisted by elevations and depressions of the land or of the ocean, which have alternately diminished and increased the land-area. This would lead to a crowding together at one time, and a dispersion at others, which would evidently afford opportunity for many previously restricted forms to enter fresh areas and become adapted to new modes of life.
From the preceding sketch it will appear, that the great subregion of Tropical South America as here defined, is really formed of three originally distinct lands, fused together by the vast lowland Amazonian forests. In the class of birds sufficient materials exist for separating these districts; and that of the Andes contains a larger series of peculiar genera than either of the other sub-regions here adopted. But there are many objections to making such a sub-division here. It is absolutely impossible to define even approximate limits to these divisions—to say for example where the “ Andes ” ends and where “ Brazil" or " Amazonia” or “Guiana” begins; and the unknown border lands separating these are so vast, that many groups, now apparently limited in their distribution, may prove to have a very much wider range. In mammalia, reptiles, and insects, it is even more difficult to maintain such divisions, so that on the whole it seems better to treat the entire area as one sub-region,
although recognizing the fact of its zoological and geographical diversity, as well as its vast superiority over every other subregion in the number and variety of its animal forms.
The reptiles, fishes, mollusca, and insects of this sub-region have been sufficiently discussed in treating of the entire region, as by far the larger proportion of them, except in the case of land-shells, are found here.
Plate XV. Characteristic Neotropical Birds.- To illustrate the ornithology of South America we place our scene on one of the tributaries of the Upper Amazon, a district where this class of animals is the most prominent zoological feature, and where a number of the most remarkable and interesting birds are to be found. On the left we have the umbrella-bird (Cephalopterus ornatus), so called from its wonderful crest, which, when expanded, completely overshadows its head like an umbrella. It is also adorned with a long tassel of plumes hanging from its breast, which is formed by a slender fleshy tube clothed with broad feathers. The bird is as large as a crow, of a glossy blue-black colour, and belongs to the same family as the exquisitely tinted blue-and-purple chatterers. Flying towards us are a pair of curlcrested toucans (Pteroglossus beauharnaisii), distinguished among all other toucans by a crest composed of small black and shining barbless plumes, resembling curled whalebone.
The general plumage is green above, yellow and red beneath, like many of its allies. To the right are two of the exquisite little whiskered hummers, or“ frill-necked coquettes," as they are called by Mr. Gould, (Lophornis gouldi). These diminutive birds are adorned with green-tipped plumes springing from each side of the throat, as well as with beautiful crests, and are among the most elegant of the great American family of humming-birds, now numbering about 400 known species. Overhead are perched a pair of curassows (Crax globulosa), which represent in America the pheasants of the Old World. There are about a dozen species of these fine birds, most of which are adorned with handsome curled crests. That figured, is distinguished by the yellow caruncular swellings at the base of the bill. The tall crane-like bird near the water is one of the trumpeters, (Psophia leucoptera), elegant
birds with silky plumage peculiar to the Amazon valley. They are often kept in houses, where they get very tame and affectionate; and they are useful in catching flies and other house insects, which they do with great perseverance and dexterity.
Islands of Tropical South America. These are few in number, and, with one exception, not of much interest. Such islands as Trinidad and Sta. Catherina form parts of South America, and have no peculiar groups of animals. The small islands of Fernando Noronha, Trinidad, and Martin Vaz, off the coast of Brazil, are the only Atlantic islands somewhat remote from land; while the Galapagos Archipelago in the Pacific is the only group whose productions have been carefully examined, or which present features of special interest.
Galapagos Islands.—These are situated on the equator, about 500 miles from the coast of Ecuador. They consist of the large Albemarle island, 70 miles long; four much smaller (18 to 25 miles long), named Narborough, James, Indefatigable, and Chatham Islands; four smaller still (9 to 12 miles long), named Abingdon, Bindloes, Hood's, and Charles Islands. All are volcanic, and consist of fields of black basaltic lava, with great numbers of extinct craters, a few which are still active. The islands vary in height from 1,700 to 5,000 feet, and they all rise sufficiently high to enter the region of moist currents of air, so that while the lower parts are parched and excessively sterilc, above 800 or 1,000 feet there is a belt of comparatively green, and fertile country.
These islands are known to support 58 species of Vertebrates, -1 quadruped, 52 birds and 5 reptiles, the greater part of which are found nowhere else, while a considerable number belong to peculiar and very remarkable genera. We must therefore notice them in some detail.
Mammalia.—This class is represented by a mouse belonging to the American genus Hesperonys, but slightly different from any found on the continent. A true rat (Mus), slightly differing from any European species, also occurs; and as there can be little doubt that this is an escape from a ship, somewhat