160—6 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
measured between the bases of the epi- and xiphiplastral forks being 6 feet 2 inchesd 
As these dimensions accord very closely with those deduced from the proportions of 
the xiphiplastron and humerus,^ they may be regarded as approximately correct. 
There are unfortunately no means of determining whether the pectoral plates of the 
male were separated by an interval, as in the males of Manouria emys. 
Humerus. — In the Cautley collection of the British Museum there is the proximal 
half of the right humerus of a gigantic tortoise from the Siwaliks referred to the 
present species by Falconer,® and figured from the preaxial aspeeP in plate XIX. 
fig. 2. of this volume, of one-fifth the natural size. Falconer® considered this 
specimen as comprising slightly less than half the complete bone, and such appears 
to be nearly the case. The length of the fragment is 14*4 inches; the larger 
diameter of the head being 5T, and the smaller 4’5 inches. The shaft is more 
contracted tlian the humerus of T. elephantina^ ; and agrees more nearly with that of 
the Galapagos T. elepliantopu^ ; from which bone the lower half of the figure is 
restored. The length of the recent bone is 8 ’4 inches ; the longer diameter of the 
head Do 6, and the shorter 1-45. Taking the former as a modulus the calculated 
length of the fossil bone would be about 28 inches (2 feet 4 inches) : this is equal to 
twice the length of the fragment (which was considered to be nearly half the bone), 
and is therefore probably not far from correct. Falconer® estimated its length at 
from 28 to 30 inches. In T. elepliantopus the length of the carapace is slightly more 
than four times the length of the humerus ; and in T. elephantina rather less than 
four times the same length (31 inches and 8‘4 inches). This would indicate that the 
length of the carapace of the largest individuals of the fossil was somewhat short of 
nine feet : this estimate agreeing sufficiently well with that derived from the 
xiphiplastron. From comparing the fossil humerus with that of a small emydine 
Falconer® estimated the length of the fossil carapace at twelve feet. The radial 
tuberosity (b) of the fossil humerus is relatively longer transversely than in T. 
elephantina, and apparently agrees closely with that of T. elephantopus. The ulnar 
tuberosity [a) projects far above the level of the head. The British Museum also 
possesses a specimen of the proximal half of the left humerus (No. 39820), and the 
head of a right humerus (No. 39820a) ; and as both these specimens agree in size 
with the figured specimen they probably indicate the average size which the largest 
(?male) individuals of the species attained. The distal extremity of the right 
humerus of a large tortoise from the Siwalik Hills in the British Museum (No. 39825) 
is figured in plate XXXI. fig. 3. of the first volume of “ Falconer’s Palseontological 
1 In all the published notices hy Falconer and Cautley (vide “Palseontological Memoirs,” vol. I. pp. 363, 374, 379) the 
length of the carapace in a straight line is given as 12 feet 3 inches, or 12 feet 6 inches, its height 6 feet, and the length of 
the plastron 9 feet 4 inches : these dimensions being generally quoted hy subsequent writers. The restored shell indicates 
that Falconer subsequently abandoned the idea of the animal having reached such enormous dimensions. 
2 Vide infra. 3 “ Palseontological Memoirs,” vol. I. p. 360. 
4 It is figured in plate XXXI. figs. 4. 5. of the above work, but misnamed the femur. 5 Op. cit., p. 361. 
6 Gunther, “ Gigantic Land-Tortoises,” pi. XVI. 7 lUd, pi. LI. figs. A. Ah 
3 Op. cit., p. 381. y Ibid, p. 361. 
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