GIANT LAND-TORTOISES 333 
tortoises are the direct descendants of the species which 
once inhabited the nearest continents, or whether they 
have been independently developed from smaller forms in 
or near their own habitats, is a question by no means easy 
to answer. Neither is it any less difficult to account for 
the complete disappearance (apparently without human 
intervention) of all the continental forms. Although the 
Siwalik mastodons, elephants, sivatheres, giraffes, hippo- 
potamuses, and other large mammals all died off, yet 
many of them left descendants (collateral or direct) in 
either India or Africa; and this makes it the more strange 
that not a single descendant of any of the Pliocene 
giant land-tortoises should have survived in any one of 
the five continents. Such, however, is the case, explain it 
how we may. 
Since the Pliocene epoch giant tortoises have been re- 
stricted to two widely sundered groups of islands. In 
modern times the islands most famous for these tortoises 
are those of the Galapagos group, which take their title 
from one of the Spanish names (galdpago) for a tortoise, 
and are situated on the equator, a comparatively short 
distance off the western coast of South America. All the 
other “ tortoise-islands” are in the Indian Ocean, where 
they lie (with the exception of the lower extremity of 
Madagascar) within the southern tropic, off the African 
coast. By far the largest of these islands is Madagascar, 
which has long been inhabited by man, and from which 
the tortoises (perhaps in consequence of his occupation) 
disappeared ages before the historic period, being known 
to us only by their sub-fossilised remains. Between the 
northern point of Madagascar and Africa lie the islands of 
the Comoro group, which had also native inhabitants of 
their own; and from these islands the tortoises likewise 
