Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/218

180 The least girth of the neck in T. robusta is 91 millimetres. The greater breadth of the neck in T. vicina, as compared with T. elephantopus, is characteristic; and the former therefore agrees with T. robusta, as, indeed, generally T. vicina would appear to possess stouter limbs than either T. ehphantopus or the still more gigantic T. ephippium. Moreover the angle formed by the junction of the glenoid and scapular articulations (fig. 2) approaches that of T. vicina. I presume, however, that the great expansions of the extremities of fig. 2 (to wit, the beetling roof of the glenoid cavity and massive proportions) make the coracoid in question one of the largest as compared with recent land-tortoises.

A portion of a left scapula, from Zebbug, of a tortoise a good deal smaller than the owner of the coracoid just described is represented in Plate VI. figs. 3, 3a, 3b. The body has been sawn through the middle, and the distal portion is unfortunately not in the collection lately presented to the British Museum by Admiral Spratt. It is otherwise imperfect, the precoracoid having been broken off close to its base (c), which is 32 millims in length by 14 millims in breadth. The sur- face for the coracoid d (fig. 3a) is triangular, and is 26 × 32 millims., and therefore much smaller than the opposing surface in Plate V. fig. 2. The glenoid cavity is slightly injured on its external border; its outline, however, seems to have been ovoid. The largest anteroposterior measurement along the curve of the cavity is 47 millims., and the maximum breadth is 28 millims.

The upper surface is flattened above the articulations, and be- comes rounded towards the middle of the body, where the transverse section (fig. 3b) forms a subelliptical outline different from the trihedral section at the same point in the scapula of T. elephantopus, and approaching rather to the greatly elongated outline of T. vicina.

The lower aspect is concave at e, below the glenoid cavity, and becomes flattened towards the body, and finally rounded at its middle. The internal border is sharp, and the outer is thick and round. The circumference of the bone just below the lip of the glenoid cavity is 97 millims.

The coracoid, as in the last, was not ankylosed to the scapula, which appears to have belonged to a full-grown tortoise of much smaller dimensions than the owners of any of the bones yet described. For that reason, and, as will be shown in the sequel, from its relationship as regards relative size with other bones, I am disposed to consider that it belonged to a distinct form or species rather than to a small individual or female of T. robusta. To this smaller-sized form I provisionally give the name of Testudo Spratti, in consideration of the valuable collections obtained by Admiral Spratt from the rock-cavity of Zebbug.

This scapula, compared with the same bone in the typical