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 he 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 ajiy 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. Belt'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 (Troohilidae), 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 Godmanf 

 remind us, the avifauna of Central America is essentially 



* Belt, J., "Naturalist in Nioaragua." 



t Salvin, O., and P. D. Godman, "Birds of Mexico and Central 

 America," 



