Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/221

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A. LEITH ADAMS ON MALTESE LAND-TORTOISES.
183
T. robusta ♂ & ♀. T. ephippium ♂.
millim. millim.
  1. Largest diameter of the humeral articulation
    ................................................................................................................................................................................................................................................................................................................................................................................................
43
40
35
  1. Largest diameter of the carpal articulation
    ................................................................................................................................................................................................................................................................................................................................................................................................
55×28
45×18
36×19
  1. Largest diameter of the proximal radial articulation
    ................................................................................................................................................................................................................................................................................................................................................................................................
37
25
30

It would be interesting to establish comparisons between the Maltese specimens and the recent and extinct Mascarene species, or, in fact, any of the recent gigantic species I have been unable to examine; the materials, however, as regards the latter are rare in public collections.

In general characters the radius of T. robusta presents large and expanding articular surfaces. The humeral is concave, and of the outline shown in fig. 2 a. The distal ulnar facet is very prominent, thus enlarging the concavity on the ulnar aspect of the bone. The gnarled surfaces for muscular attachments contrast with the general smoothness of the same parts in T. elephantopus and T. ephippium, to a less extent in T. vicina, whilst they at the same time prove that both fig. 1 and fig. 2 belong to fully adult, if not aged individuals.

The shafts in the fossil bones are round in the middle and flattened on their upper and outer aspects. The distal extremities are convex in front (fig. 2) and concave behind (fig. 1). The extensive distal ulnar facet is similar to that of T. ephippium, which appears to be relatively larger than that of T. elephantopus.

A few Tarsal and Carpal bones were found in Mnaidra Gap; but these are too much broken to be useful for comparison.

The very large Ungual Phalanges (Plate V. figs. 5, 6, 7) from Zebbug attest to the dimensions of their owners, and may be safely referred to T. robusta.

Pelvic Girdle.

Pubis.

The following pelvic fragments referable to T. robusta are contained in the Zebbug collection:—

1. A portion of a right pubis, extending from the obturator foramen outwards (including the process), is 87 millimetres in length,