280 ANNALS NEW YORK ACADEMY OF (SCIENCES 



CHELONIA 



The publication of Dr. Hay's splendid monograph'"* upon the extinct 

 Chelonia of IS^orth America has added a great deal to the available data 

 for explaining the distribution of this group. So far as the Tertiary 

 and modern distribution goes, it conforms to the same lines of dispersal 

 as do the various orders of mammals. The pre-Tertiary history of the 

 order is mostly too fragmentary to afford any important data bearing, 

 pro or con, upon the theories here presented. The whole order is in 

 general conservative and persistent to a high degree, like the Crocodilia. 



The occurrence of giant tortoises (Testudo) on several oceanic islands 

 and in Australia and Patagonia (Meiolania) has been adduced as evi- 

 dence for continental connection of these islands and for an Antarctic 

 connection of the two southern continents. Plere, as in the case of the 

 carnivorous marsupials cited on page 265, the evidence will not bear close 

 examination. In the first place, we know that large tortoises of the 

 genera Testudo and StyUmys are among the most abundant fossils in 

 the Middle and later Tertiary of the Nearctic, Palsearctic, Oriental and 

 Ethiopian regions. So far as we can judge, they were cosmopolitan, 

 except Australia and Patagonia. They occur in the Pleistocene of Cuba 

 and Madagascar and survive to the present day in certain islands in the 

 Indian Ocean and in the Galapagos Islands. So far as these oceanic 

 islands are concerned, if we assume that their presence in one involves 

 continental union, it must do so in all. If such continental union oc- 

 curred, it is hardly conceivable that, in each instance, tortoises alone 

 would have made their way to the islands. We must infer for each and 

 eveiy one of them a vertebrate and invertebrate land fauna. Where is 

 that land fauna, and why has it perished ? The idea of selective drown- 

 ing might possibly be entertained if we had to do with only a single 

 instance, but is too absurd for serious consideration, when we deal with 

 several instances of the survival of the same race. The only reasonable 

 method of accounting for the presence of Testudo on these islands is 

 that its facilities for oceanic distribution are somewhat better tlian those 

 of mammals and that it arrived by over-sea transportation. 



The most recent argument for land connection of the Galapagos 

 Islands is by Dr. Hay.'"^ He advocates a connection with Central Amer- 

 ica, via a submerged ridge which is shown in the reports of the Blake 

 Expedition to extend southwest from Costa Pica towards the islands. 



i« O. p. Hay: "Fossil Turtles of North Amorica." rarnoRie Institution Publ. No. 75. 

 1008. 

 105 O. I'. Hay, /. r. 



