154 the living animals OL THE WORLD 
these limbs take the form of flattened paddles, and in nO' 
instance are more than two of the toes provided with claws. 
The Tortoises are sub-divided by zoologists intO' 
some six or eight subordinate groups or families, for 
the most part distinguished by the respective modifi- 
cations of their protective shells. This shell in all 
tortoises and turtles consists of two essential elements — • 
the upper or back casing, known as the “ carapace,” 
and the under one, or so-called “ plastron,” which 
covers the ventral surface. In some forms these two 
elements are completely welded into one another, forming 
a continuous box-like shell ; in others they are more or 
less separate ; while in yet another series the lower 
shell is rudimentary. These distinctions have been 
found to constitute a convenient basis for classification. 
In the True Land-tortoises, which invite first 
attention, the upper and lower shells are completely 
united in a box-like form, and the neck, bent in the 
form of the letter S. can be completely retracted within 
it. The limbs are club-shaped, covered with horny 
scales or tubercles, and adapted for walking, the toes 
being unwebbed, and provided with strong claw-like nails. 
Pre-eminent among this typical terrestrial series 
come the huge Giant or Elephant-tortoises, formerly 
abundant, as their fossil remains indicate, in Southern 
Europe, India, and North and South America, and now 
represented only in the isolated oceanic islands of Aldabra, 
off Madagascar, the Seychelles, and the Galapagos groups. 
Even within historic times they were very abundant in 
the islands of Mauritius and Rodrigues; but their huge size and lethargic habits, combined 
with their esculent qualities, have brouglit bout their extermination. Those remaining in 
the islands mentioned are now so reduced in numbers that there is a possibility of their 
becoming extinct at an early date, and this notwithstanding the strenuous endeavours that 
are being made to save them. A large percentage of 
the small residue of these giant Chelonians have been 
transported from their island homes and presented to the 
London Zoological Gardens, where they are now comfortably 
housed. 
An instructive idea of the aspect and relative dimen- 
sions of these giant tortoises may be obtained by a refer- 
ence to page vii of the First Volume, in which one of 
these Chelonians is shown to be equal in size and strength 
to carrying a human rider. It is recorded that these 
reptiles were so abundant in the island of Rodrigues in 
1691 that one might count as many as 3,000 of them in 
a single flock, and walk for over 100 paces upon their 
backs. All of these giant tortoises, as obtained from 
separate island groups, or islets of the groups, exhibit 
characteristic differences, indicating the length of time 
they have been separated from one another. The 
age to which these giant tortoises attain is altogether 
phenomenal. One example at Port Louis, Mauritius, 
Phot9 by C. N. Mavroyenf^ \_Smyrna 
EUROPEAN TORTOISE 
A tortoise's shell, or carapace, constitutes a port- 
able house, mherein the animal can entirely with 
draw for shelter in inclement -weather, or -when 
attacked by enemies 
'■* I* sL . 
Photo by C N. Mavroyeni'^ \_Smyrna 
ASIATIC TORTOISES 
A tortoise, like a turtle, turned over on its back, 
represents one of the most helpless of living animals 
