TERTIARY VERTEBEATA OE THE EATtTM. 



Testudo ammon, Andrews. 

 [Plate XXIV. ; text-figs. 88-90.] 



1903. J'estudo ammon, C. W. Andrews, A Preliminary Notice of a Land-Tortoise from the Upper 



Eocene of the Fayum, Egypt (description) : Survey Dept., Cairo (with 

 a Note on the Method employed in Excavation, Strengthening, and 

 Transport, by H. J. L. Beadnell). 



1904. „ „ C. W. Andrews, Geol. Mag. [5] vol. i. pp. 527-530, pi. xvii. 



Type Specimen. — A nearly complete, slightly distorted shell, probably of a male 

 (described and figured, loc. cit. ; also text-figs. 88, 89) ; Geological Museum, Cairo. 



In this species the carapace is highly arched, the areas covered by the costal shields 

 being strongly convex. The antero-lateral and posterior marginals are strongly 

 everted ; there is a small nuchal shield. In the plastron the epiplastra are prolonged 

 forwards in the middle line into an abruptly truncated projection (at least in the 

 males). The posterior end of the plastron is notched in the middle line, and the areas 

 covered by the anal plates are sharply defined by deep grooves and notches. 



Form. & Loc. — Fluvio-marine beds (Upper Eocene) : north of Birket-el-Qurun. 



A considerable number of more or less nearly perfect shells of this species have been 

 collected, but at present little is known about the rest of the skeleton. Some humeri, 

 a part of the femur, and some other scattered remains of a large Chelonian may be 

 referred to it, and a nearly complete pelvis has been found in actual association with 

 the shell : of the skull nothing is known. 



The carapace is strongly arched in all directions, and, looked at from above 

 (text-fig. 88, A), it is somewhat quadrate in outline, owing to the eversion of the 

 marginals at the postero- and antero-lateral regions. The areas covered by the three 

 middle vertebral shields {v. 2-4) form prominent convex bosses, separated from one 

 another and from the costals by deep grooves. The anterior border of the shell 

 is notched in the middle line and somewhat upturned ; there is a small nuchal 

 shield (jiu.). The area covered by the last vertebral shield is strongly convex, as also 

 is that covered by the single pygal shield [py-). In this latter region the shell forms a 

 strong arched covering for the tail, projecting below the level of the rest of the margin. 

 The form of the bones of the carapace will be best understood from the figures 

 (PI. XXIV. fig. 1 A ; text-fig. 88, A). The neural bones {N. 1-7) vary considerably in 

 form ; thus in the specimen figured in text-fig. 88 the first is quadrate, the second 

 octagonal, the third quadrate, the fourth and fifth hexagonal, with the shorter of the 

 lateral faces in front, the sixth octagonal, and the seventh quadrate. It appears, 

 however, that in the form of the neural bones a considerable range of variation in 

 different individuals occurs (see PI. XXIV. fig. 1 a). There are three pygals {Py. 1-3), 

 which, as already mentioned, form a strongly convex protection for the tail. Anteriorly 



