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is in peculiar types of all the most characteristic American families, such as the Tanagridæ, Tyrannidæ, Cotingidæ, Formicariidæ, Trochilidæ, and Galbulidæ. A considerable proportion of the genera of the Chilian and Mexican sub-regions also occur here, so that out of about 680 genera of Neotropical landbirds more than 500 are represented in this sub-region.
Without entering minutely into the distribution of species it is difficult to sub-divide this extensive territory with any satisfactory result. The upland tract between the Amazon and Orin ooko, which may be termed Guiana, was evidently once an island, yet it possesses few marked distinctive features. Brazil, which must have formed another great island, has more speciality, but the intermediate Amazonian forests form a perfect transition between them. The northern portion of the continent west of the Orinooko has more character; and there are indications that this has received many forms from Central and North America, and thus blended two faunas once more distinct than they are now. The family of wood-warblers (Mniotiltidæ) seems to have belonged to this more northern fauna; for out of 18 genera only 5 extend south of the equator, while 6 range from Mexico or the Antilles into Columbia, some of these being only winter immigrants and no genus being exclusively South American. The eastern slopes of the Andes constitute, however, the richest and best marked province of this sub-region. At least 12 genera of tanagers (Tanagridæ, are found here only, with an immense number of Fringillidæ,—the former confined to the forests, the latter ranging to the upland plains. The ant-thrushes (Formicariidae) on the other band seem more abundant in the lowlands, many genera being peculiar to the Amazonian forests. The superb chatterers (Cotingidæ) also seem to have their head-quarters in the forests of Brazil and Guiana, and to have thence spread
Messrs. Sclater and Salvin, and Professor Newton, divide the Neotropical Region into six sub-regions, of which our “ Brazilian sub-region” comprises three-the “ Brazilian,” the “ Amazonian,” and the “ Columbian ;” but, after dae consideration, it does not seem advisable to adopt this subdivision in a general work which treats of all the classes of terrestrial animals. (See p. 27.)
into the Amazonian valley. Guiana still boasts such remarkable forms as the cardinal chatterer (Phænicocercus), the military chatterer (Hæmatoderus), as well as Querula, Gymnoderus, and Gymnocephalus; but the first three pass to the south side of the Lower Amazon. Here also belong the cock of the rock (Rupicola), which ranges from Guiana to the Andes, and the marvellous umbrella-birds of the Rio Nigro and Upper Amazon (Cephalopterus), which extends across the Ecuadorean Andes and into Costa Rica. Brazil has Ptilochloris, Casiornis, Tijuca, Phibalura, and Calyptura ; while not a single genus of this family, except perhaps Heliochæra, is confined to the exteusive range of the Andes. Almost the same phenomena are presented by the allied Pipridæ or manakins, the greater part of the genera and species occurring in Eastern South America, that is in Brazil, Guiana, and the surrounding lowlands rather than in the Andean valleys. The same may be said of the jacamars (Galbulidæ) and puff-birds (Bucconidæ); but the humming-birds (Trochilidæ) have their greatest development in the Andean district. Brazil and Guiana have each a peculiar genus of parrots; Guiana has three peculiar genera of Cracidæ, while the Andes north of the equator have two. The Tinamida on the other hand have their metropolis in Brazil, which has two or three peculiar genera, while two others seem confined to the Andes south of the equator. The elegant trumpeters (Psophiidæ) are almost restricted to the Amazonian valley.
Somewhat similar facts occur among the Mammalia. At least 3 genera of monkeys are confined to the great lowland equatorial forests and 1 to Brazil; Icticyon (Canidæ) and Pteronura (Mustelida) belong to Guiana and Brazil; and most of the Echimyidæ are found in the same districts. The sloths, anteaters, and armadillos all seem more characteristic of the eastern districts than of the Andean; while the opossums are perhaps equally plentiful in the Andes.
The preceding facts of distribution lead us to conclude that the highlands of Brazil and of Guiana represent very ancient lands, dating back to a period long anterior to the elevation of the Andean range (which is by no means of great geological anti