CHAP. xiv.J THE NEOTROPICAL REGION. 25 



is in peculiar types of all the most characteristic American 

 families, such as the Tanagridae, Tyrannidse, Cotingidse, Formi- 

 cariidae, Trochilidae, and Galbulidae. 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 land- 

 birds 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 satis- 

 factory result. 1 The upland tract between the Amazon and 

 Orinooko, 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 haa 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 (Mniotiltidse) 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 (Tanagridse) are found here only, with an immense 

 number of Fringillidse, the former confined to the forests/the 

 latter ranging to the upland plains. The ant-thrushes (Formi- 

 cariidae) on the other hand seem more abundant in the lowlands, 

 many genera being peculiar to the Amazonian forests. The su- 

 perb chatterers (Cotingidse) also seem to have their head-quarters 

 in the forests of Brazil and Guiana, and to have thence spread 



1 Messrs. Sclater and Salvin, aiid 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 due 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.) 



