REPTILES OF THE WORLD 



PART I 



THE ORDER CHE LONI A— TURTLES AND 

 TORTOISES 



From all other reptiles the Chelonians may be imme- 

 diately recognized by the "shell" — this forming a bony 

 fortress, from which are thrust the head and the limbs. 



The words tortoise, turtle and terrapin, have been 

 used indiscriminately. Some writers embrace both the 

 terrestrial and semi-aquatic species under the term tor- 

 toise, thus : — land tortoises and water tortoises, while they 

 apply the name turtle ^to the marine species only. Oth- 

 ers designate semi-aquatic and marine species as turtles, 

 and place the strictly terrestrial chelonians under the 

 head of tortoises. Terrapin is a term that has been 

 applied at one time or another, among all of the groups. 

 At the beginning, it is best to straighten this tangle and 

 the writer proposes to popularly divide the chelonians, 

 thus: 



Tortoises — The strictly terrestrial species. 

 Turtles — The semi-aquatic and marine species. 

 Terrapins — Those hard-shelled, fresh-water species 

 that are edible and have a recognized market value. 



Before going into structural details, it is necessary to 

 have a bird's-eye view of the classification ; over two hun- 

 dred species are recognized.* 



1 It is from Dr. G. A. Boulenger s admirable system of classification that 

 the writer has based his arrangement of the list given. 



3 



