332 MOSTLY MAMMALS 
as remains of other, although smaller, forms have been 
discovered in the same deposits. The nearest living ally 
of the Siwalik species appears to be Testudo emys, of the 
countries east of the Bay of Bengal, in which the shell 
does not much exceed a foot in length. Both kinds have 
the front end of the lower shell produced and notched, 
although the production and notching are much more 
pronounced in the extinct form. Both also have the horny 
shield immediately’ above the tail double, instead of (as is 
usually the case) single; and in both the skin of the legs 
contained embedded nodules of bone. 
The Pliocene deposits of the South of France have also 
yielded remains of a giant land-tortoise (7. perpiniana), 
with a shell about four feet in length, and likewise furnished 
with bony nodules in the skin of the limbs. And from 
the caves of Malta have been obtained bones of yet 
another very large species (7. robusta), apparently allied 
to the recently extinct 7. zvepta of Mauritius. 
Going farther afield, we find evidence of the existence, 
during late Tertiary times, of giant land-tortoises in North 
America, while some imperfect shells attest the former 
occurrence of another species in Patagonia. It may be, 
therefore, assumed that during the Pliocene, and perhaps 
a portion of the Miocene epoch, land-tortoises of huge 
size were spread over the greater portion of the warmer 
countries of the globe. 
With, or before, the close of the Pliocene division of 
geological time, these great reptiles seem, however, to have 
utterly vanished from all the continents of the world, and 
to have continued to exist only in certain islands, from 
some of which they likewise disappéared before or during 
the early portion of the historic period, while others have 
become extinct quite recently. Whether these island giant 
