220 



MANY REPTILES IMPLY WARM CLIMATE 



[Ch. XI. 



hemisphere at present, where the winters are long and the 

 summers cooL there is an entire absence of reptile life 

 in Tierra del Fuego, for 



exam 



Ma 



tudes 52° and 56° S.), and in the Falkland Islands. Not 



even a 



lizard, or frog, are met 



m 



these same countries we find the gnanaco (a kind of llama) 

 a deer, the puma, a large species of fox, many small rodentia 

 and, in the neighbouring sea, the seal, together with the 

 porpoise, whale, and other cetacea. 



In the arctic regions, at present, reptiles are small, and 

 sometimes wholly wanting, where birds, large land quadru- 

 peds, and cetacea abound. We meet with bears, wolves 



foxes, musk 



and deer, walruses, seals, whales, and 



narwhals, in regions of ice and snow, where the smallest 

 snakes, efts, and frogs are rarely, if ever, seen. 



The power of reptiles to bury themselves in the earth, and 

 to hybernate in a state of torpidity, enables them to exist in 

 extra-tropical regions, but not where the winter's cold is 

 excessive or of long duration. 



jf "mammalia 



explain 



i 



the struggle for 



reptiles. — In none of the secondary rocks, as before stated, 

 have any mammalia clearly referable to the placental division 

 been found, whether of terrestrial or aquatic genera. Their 

 absence may partly account for the extraordinary number of 

 genera, species, and individuals of the reptile class. For the 

 reptiles enjoyed in those periods a monopoly of a large portion, 

 of the habitable surface which they are now obliged to share 

 with the more powerful mammalia. In 

 existence they had only to compete with marsupials of verj 

 diminutive size, and, so far as we know, there were few con- 

 temporary birds, so that to a great extent the reptiles performed 

 the functions in the air, on the land, and in the water, which the 

 two highest classes of vertebrate now discharge. But granting 



that the predominance of reptiles is checked in our days by the 

 important part played by the more highly organised verte- 

 brate., we can by no means attribute the present scarcity of 

 crocodiles, iguanas, lizards, tortoises, snakes, and the larger 



batrachians 



in 



high latitudes, as 



contrasted with their 







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