164—10 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
What advantage to their owners has been the union of the pygals in nearly all 
land-tortoises, and how the advanced position and small size of the gular plates in 
the highly specialized Aldabra tortoises have helped them in the fight for supremacy, 
are questions which the writer cannot attempt to answer. 
Distribution . — Remains of this species have been obtained from the typical 
Siwalik Hills, and FalconeP refers to it certain fragments of the shells of large 
tortoises from the Siwaliks of Burma and Perim Island. It has not been found in 
the Siwaliks of the Punjab, the lower Siwaliks of Sind, or the Narbadas. 
At the conclusion of their most important memoir on this species Falconer and 
Cautley^ observed “ that there are fair grounds for entertaining the belief as probable 
that the Oolossochelys atlas may have lived down to an early period of the human 
epoch and become extinct since : — 1st. From the fact that other chelonian species 
and crocodiles, contemporaries of the Oolossochelys in the Siwalik fauna, have 
survived. 2nd. From the indications of mythology in regard to a gigantic species 
of tortoise in India.” Very little weight can be attached to any argument drawn 
from the first point ; and against it there is the circumstance that no remains of the 
species have been obtained from the pleistocene Narbadas, although this absence 
may be explained by a restricted range in space. The distribution of gigantic 
tortoises in the recent and pleistocene epochs affords, moreover, another argument 
against Falconer’s view, since all of them are found in islands where large mammals 
are entirely absent^ ; and it would, therefore, seem that these reptiles (which, from 
their distribution in time and space, evidently belong to an old group'*), although 
they originally existed on the continents and for a time lived side by side with the 
larger mammals,® were eventually ousted by the latter, and only persisted in islands 
where they were not subject to such rivalry. Now the remains of Oolossochelys atlas 
(as well as those of the somewhat smaller contemporary forms noticed below) are 
extremely rare as compared with the bones of elephants (and from the size and 
solidity of the epiplastron this part at least ought to be very frequently preserved), 
and it would thus appear that the species was one in course of extirpation by the 
struggle with the large Siwalik ma,mmals, and it is therefore improbable that it 
persisted down to the human period. 
With regard to the argument derived from mythology. Falconer and Cautley® 
base their conclusions on the improbability of the existing tortoises of India leading 
to the conception of an animal capable of supporting the world, or of holding its 
own in combat with an elephant. In the second of the two legends it is stated that 
1 “ Catalogue of Fossil Vertebrata in Mus. As. Soc. Bengal,” pp. 32, 203 (1859). 
2 ‘‘ Paleontological Memoirs,’’ vol. I., p. 369. 
3 A small elephant and hippopotamus existed with the gigantic Maltese tortoise. 
4 Vide Wallace, “ Geographical Distribution of Animals,” vol. I., p. 289 (1876). 
5 The gigantic pliocene land-tortoise of Mont Leberon, Vaucluse {vide Gaudry, “ Animaux Fossiles du Mont Leberon,” 
p. 70 [1873]), coexisted with a large mammalian fauna. 
3 Op. cit., pp. 367-8. 
