172 ORIGIN OF LIFE IN AMERICA 



probably the descendants of those which passed northward 

 from the Antilles at a time when a land connection (possibly 

 in Oligocene times) joined the latter with the old island of 

 Florida. The fauna of Florida lends some support to this 

 view. At any rate, it gives us more solid foundations for 

 estimating the nature of the physical changes which the 

 peninsula has undergone within more recent geological times. 



In the last chapter I alluded to a species of parrot 

 (Conuropsis carolinensis) which in historic times still ex- 

 tended its range as far north as the Great Lakes, and which 

 seems at present to be retreating towards its original centre 

 of dispersal in the south-east. Now this Carolina parrot, 

 as it is- generally called, has no near relations. Its 

 closest ally, Conurus, is a genus of parrot ranging from 

 Paraguay and eastern Bolivia in the south to Mexico 

 and the West Indian Islands in the north. The fact 

 of its occurrence in the West Indies alone implies that it is 

 an ancient genus, for these islands have undoubtedly been 

 separated from the continent for a long time. Moreover, 

 Cuba, Haiti, Mona Island off Porto Rico, Jamaica and St. 

 Thomas all possess distinct species of Conurus. It seems not 

 unlikely that Conuropsis is an eastern offshoot of the older 

 Conurus, just as Rhynchopsittacus has originated from it in 

 the west. The occurrence of this parrot on the mainland does 

 not necessitate the former existence of a land bridge to the 

 West Indies, but, if other facts point to it, the presence of the 

 Carolina parrot in the south-eastern States and its subsequent 

 invasion of the northern States is more readily explained 

 by it. 



I also made allusion before to the newt Spelerpes, a genus 

 confined to America and southern Europe. One of its peculiar 

 characters is that its tongue can be jerked out to a considerable 

 distance. Only one other newt peculiar to Florida and Caro- 

 lina, viz., Manculus, agrees with Spelerpes in the nature of 

 its tongue, and, like it, must be an ancient genus. Another 

 very peculiar amphibian is Amphiuma means, an eel -like 

 creature with tiny limbs, inhabiting the ditches of rice-fields 

 and swamps of the south-eastern States. No fossil remains 

 of this interesting species are known, but there can be no 

 doubt that it is a very old form. Pseudobranchus lateralis, 



