Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/219

mens of T. elephantopus and T. vicina, gives the following data. The loss of the precoracoid somewhat vitiates the determination as to the angle formed by the union of the scapula and that bone. It would appear, however, to have been more obtuse than in either of the above-named recent species. As to available dimensions:—

	T. elephantopus.	T. vicina.	T. Sprati.
	millim.	millim.	millim.
Maximum breadth at the glenoid cavity ................................................................................................................................................................................................................................................................................................................................................................................................	77	77	73
Girth at the middle of the shaft ................................................................................................................................................................................................................................................................................................................................................................................................	75	75	70
Length of glenoid cavity ................................................................................................................................................................................................................................................................................................................................................................................................	50	55	45

 

Humerus.

The proximal extremity of a right humerus from Zebbug (Plate VI. figs. 6, 6a) is the only specimen of that bone in the collections. It was picked up by me among the debris of the Zebbug rock- cavity several years subsequent to Admiral Spratt's explorations. This humerus evidently belonged to a rather smaller individual than the owner of the femur (Pl. 71. figs. 5, 5a, 5b), and to a tortoise about the size of Lutremys europæa, with whose femur it agrees closely in characters and dimensions. The large tuberosity diverging from the head expands and rises considerably above the latter, whilst the smaller tuberosity is nearly on the same level with the head. The intervening pit is deep and broad. The head is elliptical, and measures 11 millimetres along its curve, and has a deep pit under it. The least girth of the shaft is 13 millimetres. On the radial side of the head at b, fig. 6, is a groove with a sharp outer margin.

As compared with Lutremys europæa these characters are absolutely identical. In T. græca the great tuberosity is not nearly so much expanded, and the groove b (fig. 6) is wanting; the shaft, also, is stouter, and there is no pit under the head. Considering that the affinities with Lutremys europæa are also confirmed by the femur (fig. 5), I do not, in the absence of further data, deem it necessary to separate the fossil from this recent freshwater species, an adult specimen of which in the British Museum has a humerus of 44 millimetres and a carapace of 210 millimetres. This tortoise is still found in the lakes and muddy waters of Sardinia, Italy, and elsewhere in Southern and South-eastern Europe,