Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/222

184 the maximum breadth of the process being 24 millimetres. The same measurements of the pubis of T. ephippium are 76 and 18 millimetres.

2. A mutilated process of another pubis presents about the same measurements.

3. A fragment of the symphysial end of a right os pubis indicates a tortoise as large as the owner of the preceding, but shows no important characters.

Two proximal extremities of femora of gigantic tortoises were found by me in Mnaidra Gap. The left, being the more entire, is represented in Plate V. figs. 4, 4 a, 4 b.

It shows the head, trochanters, and a small portion of the shaft. There is a loss of substance on the outer side of the head and great trochanter, which, however, is preserved in the other specimen of the right side. There is also a small abrasion on the inner side of the head. Otherwise the fragment is entire and well preserved. It will be seen from the figures that the head is elliptical, and does not rise above the summit of the great trochanter.

The conspicuous notch (fig. 4 a) is also present in the recent Testudo ephippium, and is apparently wanting in T. elephantopus : thus the femur of the former and that of T. robusta agree so far. Moreover the cartilaginous capping of the trochanters is apparently confined to the latter by a smooth dividing groove, whereas in T. elephantopus the cartilage extends along an unbroken ridge from trochanter to trochanter.

The condition of the fossil renders it impossible to state whether or not one or other of these two conditions existed.

The pit embraced between the head and the trochanters is about as broad as long; and the notch between the head and small trochanter is broader than between the former and the great trochanter, but it is relatively smaller than in T. elephantopus and T. ephippium. And whilst the head in the former and in T. robusta assimilate, T. robusta and T. ephippium consort as to the intertrochanteric notch and the configuration of the intervening pit (fig. 4 b).

A detached left femur of a recent tortoise (No. 1021 in the Osteological Collection of the Royal College of Surgeons) agrees with the characters of T. ephippium and T. robusta; but the cartilaginous covering dips into the notch, and is continuous from one trochanter to the other.

The locality from which this specimen was obtained is unknown; but it evidently belonged to a very large tortoise, and an individual of nearly the dimensions of the fossil. The greatest length and breadth of the heads in the three (by callipers, and along the curve) are as follows:—