The most remarkable feature in the geographical distribution of the Passeres is the richness of the American continent, and the large development of characteristic types that occurs there. The fact that America possesses 14 altogether peculiar families, while no less than 23 Old-World families are entirely absent from it, plainly indicates, that, if this division does not represent the most ancient and radical separation of the land surface of the globe, it must still be one of very great antiquity, and have modified in a very marked way the distribution of all living things. Not less remarkable is the richness in specific forms of the 13 peculiar American families. These contain no less than 1,570 species, leaving only about 500 American species in the 13 other Passerine families represented in the New World. If we make a deduction for those Nearctic species which occur only north of Panama, we may estimate the truly Neotropical species of Passerine birds at 1,900, which is almost exactly {302}_one-third_ of the total number of Passeres; a wonderful illustration of the Ornithological riches of South America. _Order II.--PICARIÆ._ FAMILY 51.--PICIDÆ. (36 Genera, 320 Species.) GENERAL DISTRIBUTION. __________________________________/\__________________________________ / \ NEOTROPICAL| NEARCTIC |PALÆARCTIC | ETHIOPIAN | ORIENTAL | AUSTRALIAN SUB-REGIONS|SUB-REGIONS|SUB-REGIONS|SUB-REGIONS|SUB-REGIONS|SUB-REGIONS. -----------+-----------+-----------+-----------+-----------+------------ | | | | | 1. 2. 3. 4 |1. 2. 3. 4 |1. 2. 3. 4 |1. 2. 3 -- |1. 2. 3. 4 |1 -- -- -- | | | | |