Page:Quarterly Journal of the Geological Society of London, vol. 34.djvu/165

Rh meaning "toward the proximal end" and "toward the palmar side" of the bone.

In the proximal end of the humerus, figured in Plate VI., the following parts are noted:—

a. Articular head.

b. Radial tuberosity (answering to the "greater tuberosity," or tuberculum majus, of anthropotomy).

c. Ulnar tuberosity ("lesser tuberosity," or tuberculum minus of anthropotomy).

d. Scapular groove, lodging the lower border of the glenoid surface of the scapula (part of the "neck of the humerus" of anthropotomy).

e. Ligamentous pit or surface, receiving the anterior coracoid ligament.

f. Subtuberous fossa, with "foramen pneumaticum."

g. Radial border of ditto.

h. Tricipital ridge.

i. Pectoral crest.

k. Ancono-deltoid ridge.

l. Distal radial border of humerus.

m. Prebrachial depression.

n. Ectepicondylar process.

The subject of figs. 1–3 includes, of the left humerus, the articular head (a), the base of the radial tuberosity (b), that of the ulnar tuberosity (c), with the intervening scapular groove (d), the beginning of the tricipital crest (h), and that of the pectoral crest (i). In what remains of the subtuberous fossa part of a pneumatic foramen (f) is preserved; a greater proportion of the pneumatic fossa is shown in the right humerus (fig. 3, f').

The head (fig. 3, a), or proximal articular surface, is, as usual, elongate and moderately convex in the radio-ulnar direction, more convex across the shorter ancono-palmar diameter. It is characterized by its large relative size as compared, for example, with that in the albatross (Diomedea exulans), ib. figs. 4–6; and differs from the humerus in that and other birds in the degree and extent of the con- cavity longitudinally, or in the direction of the long axis (fig. 3, a') at the radial third part of the surface. The humerus of the Marabou (Ciconia marabou, Temm.) offers a feeble approach to this character.

The radial or outer tuberosity (b) has lost its outer layer; the cancellous structure is exposed by abrasion. The rising or smooth ridge (fig. 2, h), continued from the anconal part of the tuberosity upon the shaft below, is better marked than in Vultur monachus, still more so than in the marabou, pelican, and albatross, in which it is barely definable. The ulnar or inner tuberosity (c) is bent anconad, leaving a (scapular) groove or canal (d) between it and the head, wider and shallower than in the vulture, marabou, crane, and pelican, but less wide and shallow than in the albatross (fig. 4, d). Of the shape and extent, however, of this tuberosity the worn and fractured state of the fossil prevents a judgment.

The palmar part of the head (fig. 1, a), though abraded, projects further over that surface of the shaft than in any other bird with which I have compared the fossil. In the extent of the flat