GIANT TORTOISES AND THEIR DISTRIBUTION 311 



and Patagonia, and other upper and middle Tertiary deposits. 

 The Maltese species, it may be observed, is believed to have 

 been nearly related to the extinct Mauritian T. incpta, while the 

 two French species have been affiliated to the existing African 

 T. calcarata and T. pardalis. 



Last and most important of all is the giant extinct tortoise 

 from the Upper Eocene strata of the Fayum district of Egypt 

 described by Messrs. Andrews and Beadnell under the name of 

 Tcstudo amnion, since this carries back the group to a much 

 earlier epoch than any of the others. This species agrees with 

 T, atlas in the absence of a nuchal shield and the divided gulars, 

 although the latter are not produced into horn-like processes, 

 a character in which the Egyptian species resembles T. cautleyi, 

 another species from the Indian Siwaliks, and the modern 

 T.sumeirci of the Seychelles. In the words of its describers, 

 " it seems probable that in the present [Egyptian] species we 

 have an early representative of a large group of tortoises, 

 members of which occur at several horizons in the Tertiary beds 

 of Europe, and of which [the African] T. pardalis and T. calcarata 

 may be the modern forms. T. atlas and T. cautleyi of the Siwalik 

 Hills and the existing T. sunieirei may also fall into this group." 



From the foregoing survey it will be apparent that giant 

 tortoises existed in Northern Africa in the later portion of the 

 Eocene, and that during the Miocene and Pliocene divisions of 

 the Tertiary period they were distributed over the greater part 

 of the earth's surface. Further, these giant Tertiary tortoises, 

 which were doubtless more or less nearly related to the modern 

 insular forms, appear to have left two smaller descendants on 

 the African continent, although these differ from the living 

 island species by their variegated coloration. 



Two points— one of which leads on to important problems 

 in connection with the origin of the islands inhabited by modern 

 giant tortoises — remain for consideration. Firstly, why did 

 these reptiles disappear from all the continents, to survive in 

 two widely sundered groups of tropical islands ? secondly, how 

 did they reach these islands? 



As regards the first question, it is evident, as indicated above, 

 that it was not the competition of large forms of mammalian life 

 that led to the extinction of giant tortoises on the continents, 

 since the largest of all — the Indian Tcstudo atlas — flourished 

 alongside of a mammalian fauna comparable to that of modern 



