TESTUUO AMMON". 
281 
n, female. Anteriorly the epiplastral projection is truncated at right angles to the 
long axis of the shell, and is slightly notched in the middle line. The posterior angle 
of the rather large entoplastral is on or a little behind the groove between the 
humeral {Ji.) and pectoral (iject.) shields. The posterior border of the xiphi})lastral 
region {Xip.) forms a wide, open, V-shaped notch. The gular shields (y.) are paired, 
and the pectorals {pect.) are very narrow; the region covered by the short anals {an.) 
is considerably narrower than the part immediately in front of it, from which it is 
marked off by a deep groove. 
In addition to the absence of the prolongation of the epiplastrals and the flatness of 
the plastron as a whole, the shell figured on PI. XXIV. differs from the type specimen 
in the following points: — (1) it is much smaller; (2) the areas covered by the vertebral 
shields are less convex; (3) the caudal region is less convex inferiorly ; (4) the shell, 
as aAvhole, is relatively rather longer and narrower; (5) the groove between the costal 
and marginal shields is deeper ; (6) the anterior portion of the plastron, in front of a 
transverse line passing through the hinder angle of the gular shields, is turned upwards 
and greatly thickened above so as to form a sort of lip, behind which it thins again 
abruptly ; (7) the anal region and the posterior notch are narrower. 
These differences do not seem to be of great importance, and may be partly due to 
age, partly to sex ; at the same time, although for the present this specimen is referred 
to T. ammon, the possibility that it may belong to another species must not be lost 
sight of. It is, perhaps, the most nearly perfect shell of a Lower Tertiary tortoise ever 
found, being undistorted and unbroken, and looking like a recent specimen ; it, like the 
type specimen, was collected by Mr. H. J. L. Beadnell. 
Of the recent gigantic Land-Tortoises T. ammon seems to approach most nearly to the 
Aldabra and Madagascar forms, having like them a nuchal shield and paired gulars. 
In the general form of the carapace, especially the convexity of the vertebral shields, 
it is similar to T. gigantea, Schweigger {T. eJephantina, Gunther), of North Aldabra *, 
but in that species the anterior and posterior marginals are smaller and less everted, 
and the shell is wider behind than in front. In the plastron also some points of 
similarity exist : in both it is large, the epiplastral region is prolonged forwards and 
truncated, and the xiphiplastral border forms an open notch ; on the other hand, 
in the fossil the plastron is relatively larger, the anterior and posterior lobes narrowing 
very little towards their extremities. 
Numerous Land-Tortoises of large size are known from various horizons in the 
Tertiary beds of Europe and India. T. gigas, Bravardf, from the Upper Oligocene 
* Giinther, The Gigantic Land-Tortoises (Living and Extinct) in the Collection of the British Museum, 
pis. iii. & iv. fig. A ; also Proc. Linn. Soc. 1898, p. 14. 
t Bravard, Considerations sur la distribution des Mammiferes terrestres fossiles dans le Departement du 
Puy-de-Dome, p. 15 (Clermont-Ferrand, 1844); also Gervais, Zoologie et Paleoutologie franc^aises, ed. 2 
(1859) p. 436, pi. liv. 
2o 
