CHAPTER III : THE SNAPPING TURTLES 



FAMILY CHELYDRID^E 

 A Small Family, Composed of Three Large and Powerful Species 



Classification. Of the three species composing the family 

 Chelydrida, two inhabit North America. The family is divided 

 into two genera, Chelydra and Macrocbelys. One species of the 

 former is widely distributed and abundant in the United States 

 and ranges southward to Ecuador; the other species inhabits 

 Mexico and Guatemala. The single species of Macrocbelys is 

 confined to the Southern United States. 



General characters. The Snapping Turtles are the largest 

 of the fresh-water chelonians inhabiting the United States. 

 Their general form is well known. The dull, rough carapace, 

 with its heavy keels and marginal serrations, the proportionately 

 huge and sinister head, and the long, fleshy tail, with its alligator- 

 like crest combine to make these turtles unique. The plastron 

 is insignificantly small and narrow and affords comparatively 

 no protection but these big turtles do not seek to withdraw 

 the head and limbs like their smaller and weaker relations. 

 They are bold and aggressive fighters and their massive, keen- 

 edged jaws cause them to be the terror of most of the aquatic 

 and semi-aquatic creatures. 



The Common Snapping Turtle (Cbelydra serpentina), though 

 larger than any other species of North American turtle, except 

 its near ally, is dwarfed by the comparison of the latter species 

 the Alligator Snapping Turtle (Marcochdys lacertina). Adult 

 specimens of this enormous, fresh-water turtle attain a weight 

 of 130 and 140 pounds. 



The genera may be defined, thus: 



Under surface of tail with large shields. . . . Chelydra. 

 Under surface of tail with large scales. . . Macrochelys. 



Besides these characters the following points may be em- 

 ployed in separating the two species inhabiting the United 

 States: 



ii 



