126 ORIGIN OF LIFE IN AMERICA 



known to science. Eumeces must have lived in North 

 America possibly since early Tertiary times. The genus has 

 also been observed in India. One of the species ranges from 

 Baluchistan, right through Persia, Syria and Egypt to Tunis, 

 having there probably given rise to the allied form confined 

 to Algeria and Morocco. 



If Eumeces had already existed in south-western North 

 America in early Eocene times, we should expect it to have 

 travelled to South America during the supposed Eocene land 

 connection with that continent. That it has not done so may 

 be due to the fact that its original home is in south-eastern 

 Asia. This assumption is strengthened by the circumstances 

 that its nearest relations are the genera Tribolonotus of New 

 Guinea, and Brachymeles of the Philippine Islands. 



Since Lygosoma, like Eumeces, also occurs in the south- 

 western States, it may likewise have made its entry into North 

 America in that region, though its original home seems to have 

 been somewhere in the western Pacific. Being probably an 

 older genus than Eumeces, both may, nevertheless, have taken 

 the same route in reaching North America. Where that route 

 lay and what were the geographical features of North America 

 at the time will be discussed later on when more material has 

 been gathered from other sources. 



I alluded above to another lizard which has penetrated as 

 far north as New Jersey, namely, the swift (Sceloporus undu- 

 latus) , so called from the great activity and speed of its move- 

 ments.* Its scales are strikingly different from those of the 

 skinks. They are large and coarsely keeled, terminating in 

 sharp, bristly points. The swifts belong to the typically 

 American family Iguanidae. All the Iguanidae, and there are 

 many of them, are confined to North and South America, with 

 the exception of one genus which inhabits the Fiji Islands 

 and two others living in Madagascar. It is quite possible, 

 however, as Dr. Gadowf suggests, that the Madagascar genera 

 represent cases of convergent evolution from some common 

 ancestor. 



Although a species of Iguana has been described from the 



* Ditmars, E. L., " The Eeptile Book," p. 123. 

 t Gadow, H., " Amphibia and Keptiles," p. 501. 



