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 



