DIVISIONS OF REPTILIA. 263 
our shores. It is of comparatively small size—not more than 
about three feet in length—but is of considerable commercial 
importance, as it furnishes the “tortoise-shell” of trade, so 
largely used in various kinds of ornamental work. 
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Fig, 141.—The Hawk's-bill Turtle (Chelone tmbricata)—after Bell. 
The Sea-tortoises or Turtles have ithe carapace much flat- 
tened, the legs of unequal length, in ‘the form of solid fins or 
oars, the toes being conjoined, and hardly distinct from one 
another. 
The Marsh, Pond, and River Tortoises are generally fur- 
nished with webbed feet, and lead an amphibious, semi-aquatic 
existence. The so-called “Soft Tortoises” (Zrzonycide) be- 
long here, and are distinguished by the imperfect condition 
of the carapace, which is simply covered with a leathery skin. 
A good example is the Soft-shelled Turtle (7. fervor) of the 
Southern States. Here also belong the Snapping-turtles, so 
well known in the person of the common American species 
(Chelydra serpentina), and the Terrapins (Zmydide), of 
which many forms are found in all parts of the United States. 
In the curious little Box-tortoise (Czstudo Virginea) the plas- 
tron is composed of two movable portions which can be 
brought into accurate apposition with the carapace, thus com- 
pletely protecting the animal within. 
