TESTUDO AMMON. 281 



a 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 (Ent.) is on or a little behind the groove between the 

 humeral (h.) and pectoral (pect.) shields. The posterior border of the xiphiplastral 

 region (Xtp.) forms a wide, open, V-shaped notch. The gular shields {g.) 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 a whole, 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. elephantina, Giinther), 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, Bravard f , from the Upper Oligocene 



* Giinther, The G-igantic Land-Tortoises (Living and Extinct) in tlie Collection of tiie 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 Deparlement du 

 Puy-de-D6me, p. 15 (Clermont-Ferrand, 1844); also Gervais, Zoologie et Paleontologie frangaises, ed. 2 

 (1859) p. 436, pi. liv. 



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