The Snapping Turtles 



a. Three moderate keels on the carapace. 

 Colour. Very dark olive, or dark brown. 



COMMON SNAPPING TURTLE, Cbelydra serpentina. 



Distribution. North America east of the Rockies; 

 southward to Ecuador. 



b. Three very high keels on the carapace. 

 Colour. Pale brown or yellowish. 



ALLIGATOR SNAPPING TURTLE, Macrochclys laceriina. 



Distribution. Rivers emptying in the Gulf of 

 Mexico Florida to Texas; northward to Missouri. 



The Snapping Turtles are herewith considered in detail: 



THE COMMON SNAPPING TURTLE 

 Cbelydra serpentina, (Linn.) 



Large specimens will weigh about forty pounds and such 

 would have a carapace about fourteen inches long. 



The carapace is very sharply serrated in the rear. There 

 are three blunt, broken keels, rising as tubercles at the rear 

 margins of the shields through which they pass. The carapace 

 of old individuals is quite smooth. With young specimens 

 there are radiating lines or ridges from the higher portions of 

 the keels. Very young specimens are exceedingly rough. See 

 Fig. The plastron is small and narrow, exposing a great amount 

 of the fleshy parts. 



The under-surface of the tail is covered with large shields. 



As with all of the very aquatic chelonians the feet are broad 

 and extensively webbed. Both front and rear pairs are pro- 

 vided with large and coarse nails. 



Most characteristic about this, and the allied species, is 

 the huge, powerful head; the upper and lower mandibles ter- 

 minate in strong hooks. Though the eyes are comparatively 

 small, they are very keen of vision. The head cannot be com- 

 pletely withdrawn into the shell, nor can the tail nearly as 

 long as the upper shell be protected beyond folding against 

 the lower margin of the shell. 



Colouration. Carapace, dull olive or dark brown, with 

 little or no markings; plastron dull yellow. The upper portion 

 of the head is very dark as is the upper-surface of the limbs 

 and tail; beneath, these members are yellowish. 



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