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, R. L., “The Reptile Book,” p. 123. 
t Gadow, EL, “ Amphibia and Reptiles,” p, 501. 
