TORTOISES 231

and turtles, distinguishable enough from the other
reptiles by their armour alone. There are four
groups of them, the sea turtles, the fresh-water turtles,
the fresh-water tortoises, and the land _ tortoises.
There are two groups of sea turtles, the hard-shelled
ones and the leathery ones. The leathery ones are a
very old group, but are now represented by only one
species, Dermochelys coriacea, which is occasionally
over six feet long, and is found in most temperate and _
tropical seas, being inso many respects peculiar that
some assign it to a special order devoted to itself and
its long line of ancestors. If we admit this order,
Athecaia, all the other chelonians will go to Testaudt-
nata, and give no difficulty in sortation, for the
marine turtles have feet like paddles ; the freshwater
turtles have webbed feet with sharp claws on the
three inner digits like the crocodile, and their upper
shells or carapaces are covered with skin; the fresh-
water tortoises have a plated carapace and long sharp
claws to their feet ; and the land tortoises have club-
shaped feet with blunt claws.

The land tortoises do not eat cockroaches or
vermin, but are vegetarians. Some of them, like
Testudo mauritania, sold in the streets, are but a few
inches long ; others, like those of the Galapagos and
Mascarene Islands, are giants. They all have a
domed carapace, which in the larger species can be
pierced with a knife when alive. At South Kensington
there is a land tortoise, brought home by Captain
Cookson from Aldabra in 1875, which is known to have
been more than eighty years old and to have weighed
nearly eight hundredweight. The fresh-water tor-