Ch.\p. m. CIIELONIAN FAUXiE. 449« 



ridge on the same surface which fits into the furrow of the lower jaw is sharper 

 and more prominent than in Clielonoidis, and is not tuberculated. To this genus 

 belongs the large Galapago Turtle, Testudo indica, a living specimen of which 

 was sent to me by Mr. Patrick II. Frey, of New York. 



The genera above described may be readily distinguished from Testudo graeca, 

 which is the type of the genus Testudo propei'. In the latter, the outer furrow 

 of the alveolar surface of the upper jaw passes round the front end without inter- 

 ruption, and with little change in width ; the ridge which fits into the furrow 

 of the lower jaw is very short, being interrupted by a long space in front ; the 

 inner edge of this surface descends only for a short distance from the hind end 

 forward. In the alveolar surface of the lower jaw the furrow and inner ridge 

 are very short, and the long, steep surface in front of them turns around the 

 end with a broad curve. Chersus, Waffl., is at once distinguished by the mova- 

 bility of the posterior lobe of the sternum, but differs also in the scales of the 

 legs. It is founded on Testudo marginata. Psammobates, Fits., is well characterized 

 by the small scales which uniformly cover the four plantigrade feet. To it belong 

 the well-known Testudo radiata. 



SECTION X. 



CHELONIAN FAUN.E OF NORTH AMERICA. 



The more minutely the geographical distribution of animals is investigated, the 

 more do regularity and order appear to exist among them in this respect; so 

 much so, that I strongly entertain the hope that naturalists may one day read 

 the design which has presided over this arrangement. Owing to the extensive 

 contributions I have received for my investigations from every quarter of the 

 country, and particularly from the collections of the Smithsonian Institution, which 

 contain specimens from the least explored parts of the continent, I have been 

 able to trace the natural boundaries of all our Testudinata with a much erreater 

 degree of accuracy than has hitherto been done. The long lists of localities from 

 which I have seen specimens of the different species enumerated in the preceding 

 sections, and the names of the observers to whom I am indebted for them, will, 

 I trust, afford a satisfactory guarantee for the accuracy of the generalizations derived 

 from their study. 



The most striking result of these comparisons is the certainty thus acquired, 

 that, while certain genera and species have a very wide range, others are circum- 



5G a 



