192 NATURAL HISTORY. 
living. There are four families—Land Tortoises, Marsh 
Tortoises, River Tortoises, and Marine Tortoises or Tur- 
tles. 
316. The Land Tortoises have short stumpy feet, some- 
what like those of the Elephant, the toes not being sepa- 
rate, and the claws alone being apparent. They are, for 
the most part, inhabitants of the warmer regions, though 
some species live in colder climates, passing the winter, 
however, in a state of hibernation. Some very large spe- 
cies are found in and near the tropics. Thus, at the Gal- 
lipagos Islands, there are great numbers of Land Tor- 
toises weighing over two hundred pounds. The food of 
the Land Tortoises is wholly vegetable. They are quiet, 
inoffensive animals, never making any attack, and when 
attacked they draw their extremities and head wholly 
within their portable house. 
317. The Marsh Tortoises form an extensive family, dif- 
fused through the warmer countries of both continents. 
They are found in swamps, lakes, ponds, and small riv- 
ers. They swim easily, as their feet are expanded, and 
have a web between the toes. Their covering is not as 
firm as that of the Land Tortoises. The River Tortoises 
are another simular family, found in the large rivers. The 
American Snapping Turtle, which devours such quanti- 
ties of young Alligators, belongs to this family. There 
is a similar ‘species in the Nile equally destructive to the 
young Crocodiles. Both of these families are carnivo- 
rous, living on fish, reptiles, birds, and insects. The bony 
plates of the carapace of the River Tortoises are thinner 
than those of the Marsh Tortoises, and they are some- 
what imperfect. Besides, the carapace has a coating of 
a leathery character in place of the horny plates of the 
previously noticed families. These animals are therefore 
sometimes called Soft Tortoises. 
318. The Marine Tortoises or Turtles have their feet 
modified so as to be really fins or flippers. The anterior 
pair are most developed, as seen in Fig. 157, the Green 
