ZOOLOGY. 295 



fauna. These tortoises attained a varying size ; some even 

 reached a weight of nearly, if not over, 500 pounds, and had 

 shells over six feet long, but most were much smaller. Liv- 

 ing to a very great age and with no redoubtable enemies to 

 contend with, they were found by the early visitors to the 

 islands in question in great numbers. According to Leguat, 

 for example (in 1691), "There are such plenty of land turtles 

 in this isle [Rodriguez] that sometimes you see two or three 

 thousand of them in a flock, so that you may go above a 

 hundred paces on their backs." These numbers, however, 

 were soon diminished ; the animals afforded savory and 

 nutritive meat which formed a most agreeable variety for 

 the mariner, and consequently they were taken in quantity 

 and stored on shipboard for future consumption. Only the 

 difficulty of access to the islands prevented their complete 

 annihilation. 



The question arises, What is the significance of the occur- 

 rence of these animals in such widely remote regions without 

 any representatives in intermediate ones? "The natural- 

 ists," says Dr. Giinther, "who maintain a common origin for 

 allied species, however distant in their habitats, will have to 

 assume a former continuity of land . . . between the Masca- 

 renes and Africa, between Africa and South America, and, 

 finally, between South America and the Galapagos. A conti- 

 nuity of land in this direction is more probable than one in 

 the opposite hemisphere, which would extend over 210. In- 

 deed, the terrestrial and fresh-water faunse of Tropical Amer- 

 ica and Africa offer so many points of intimate relationship 

 [see, e. </., Annual Record for 1876, p. clxvii] as very strongly 

 to support such a theory. The tortoises, then, would be as- 

 sumed to have been spread across the whole of this large 

 area, without being able long to survive the arrival of man 

 or large carnivorous animals." In the face of any formi- 

 dable enemies, great size in such animals would be disadvan- 

 tageous, inasmuch as it would render them conspicuous and 

 prevent them from obtaining shelter, while their defensive 

 ability would not be correspondingly increased ; small size 

 would be advantageous in relation to their environments, 

 and hence small species of the same genus have survived 

 and still exist over large continental areas. 



