As regards its Bird-life the Neotropical Region, which, according to the
arrangement usually adopted, consists of America south of the Isthmus of
Tehuantepec together with the West Indies[1], may be most conveniently
divided into six Subregions. These are:--
[1] _Cf._ Sclater, Journ. Linn. Soc., Zool. ii. p. 143 (1857).
1. The _Transpanamic Subregion_, embracing the great Central-American
Isthmus from Tehuantepec down to Panama.