249 



From my previous remarks (p. 152) it would appear as if the 

 raccoon family (Procyonidae) had originated in some western 

 land in America, and yet the genus Cercoleptes (Potos), which 

 belongs to this family, is certainly an invader from the south. 

 Indeed, when we examine the range of the members of this 

 typically American family of Procyonidae, we notice the 

 peculiar feature that almost all the species are confined to the 

 Pacific coast. The raccoon (Procyon lotor) no doubt has ex- 

 tended its range to the eastern States, while the allied species 

 Procyon maynardi, as we have learnt, is even confined to the 

 Bahama islands, and one, the coati (Nasua rufa), has a wide 

 distribution in South America from Bolivia eastward. Almost 

 all the other members of the family, however, inhabit 

 curiously disconnected areas in the vicinity of the Pacific 

 Ocean. Bassaricyon lives in Ecuador, Panama and Costa 

 Eica. One species of Bassariscus is peculiar to the island 

 of Espiritu-Santo near lower California, another ranges from 

 Mexico to the western States, a third occurs in western 

 Mexico, Guatemala, Costa Rica and on Mount Chiriqui, in 

 western Panama, at a height of 6,000 feet. Of the ccxatis 

 (Nasua), one species passes from Mexico northward to Cali- 

 fornia and southward to Costa Rica, another is confined to 

 the island of Cozumel, a third lives in the Ecuador mountains 

 at a height of 7,000 feet, whereas Nasua olivacea is met. 

 with in Santa Fe de Bogota and in the Merida of Venezuela 

 at heights up to 12,000 feet. Altogether it looks as if the 

 members of the family Procyonidae had spread from various 

 western foci. Some of them may have retained their original 

 distribution, while the more adaptable genera sent outposts 

 eastward into the great continents. The early stages of this 

 evolution must have taken place before either Central America 

 or South America had become consolidated into anything like 

 their present shapes. Later on I shall have occasion to dis- 

 cuss other similar cases of discontinuous distribution occur- 

 ring among the lower vertebrates. All of these appear to be 

 due to the same peculiar features in the physical geography 

 of Tertiary America. 



In eastern Mexico we make our first acquaintance with 

 monkeys. In early Eocene times, as already mentioned, 

 monkeys, belonging to extinct groups, probably entered the 



