250 
ORIGIN OF LIFE IN AMERICA 
United States from the south. They seem to have had a short 
existence in North America, for no trace of them has been 
noticed in later deposits. Ever since renewed facilities for a 
northward advance occurred an entirely new invasion has 
taken place, and one of the “ howlers ” can now be heard at 
night even in the forests of Vera Cruz in eastern Mexico. A 
spider monkey (Ateles vellerosus) may be seen in the, same dis¬ 
trict gracefully swinging from branch to branch. These 
monkeys differ in distribution from the raccoon family in so 
far as they have their centre of distribution in Brazil and 
northern South America, from which they no doubt invaded 
Central America in more recent geological times. There are 
other families of mammals which we meet here for the first 
time. We need not dwell on them any longer, as we shall 
have occasion to become acquainted with them in subsequent 
chapters. 
The wealth of new bird life in Central America is very 
striking, and is vividly described in Mr. Bolt’s * delightful 
book of travels in Nicaragua. Among the more noteworthy 
families are the toucans(Rhamphastidae),with their enormous 
gaily-coloured bills, the humming-birds (Trochilidae), a great 
variety of parrots, the peculiar curassows and many others. 
Some of these of course, like the humming-birds, enter the 
United States largely during their northward migrations, and 
to some extent are resident in the southern States. I should 
also mention the most beautiful of all birds, the quesal 
(Trogon resplendens), or royal bird of the Aztecs as it has 
been called, with its delicately tinted plumage of metallic 
green and blue, and its long waving plumes. The Trogonidae 
now have their headquarters in Central and South America, 
but Trogon gallicus occurs in France in Miocene deposits; 
and this seems to suggest in what manner the early members 
of the family crossed over to Africa and the Oriental Region, 
where some genera are still found living; the discontinuous 
range corroborating the palaeontological evidence of the great 
antiquity of the group. As Messrs. Salvin and Godman f 
remind us, the avifauna of Central America is essentially 
* Belt, J., “Naturalist in Nicaragua.” 
t Salvin, O., and F. D. Godman, “ Birds of Mexico and Central 
America,” 
