BHUFELDT. ] OSTEOLOGY OF THE EREMOPHILA. 645 
compared with the other bones of the arch; the coracoids more de- 
pressed, 7. e., more in line with the sternum; and the furculum in its 
direction backwards showing a gentler curve. 
The upper extremity—(P1. IV, Figs. 22, 31, 36, and 43).—The pectoral 
limb in Hremophila maintains ‘the usual ornithic characters of a great 
number of the class, both in arrangement and number of the bones com- 
prising it. The skeleton arm has ten distinct segments; of these, we 
find one devoted to the brachium, two to the antibrachium, two to the 
carpus, one to the metacarpus, and four to the phalangeal portion of 
the manus. 
The bone humerus in this bird is more remarkable for its lack of curv- 
ature than anything else, being short and straight, as in others of the 
suborder among which our subject is classed and belongs. 
The head of the bone is broad and moderately flexed anconad, develop- 
ing only a very narrow and thin radial crest, which is bent for its entire 
extent toward the palmar aspect. This crest, answering to the ‘‘ greater 
tuberosity” of anthropotomy, and giving attachment to the usual mus- 
cles, extends along on a straight line on the upper aspect of the shaft 
longitudinally for only about half a centimetre. 
The ulnar tubercle, or lesser tuberosity, makes up the thickened and 
proximal border of the confines of the pneumatic foramen; a deep little 
pit on its palmar side or margin lodges the extremity of a strong liga- 
ment coming from the head of the coracoid of the same side, and mate- 
rially assists in keeping the head of the humerus in its socket. 
The elliptical and convex articulating facet of the head curls over an- 
conad, and from its middle a line runs down the bone for a short dis- 
tance, being one of the angular boundaries of this the trihedral extrem- 
ity of the bone. Quite a notch exists between the facet just described 
and the wall of the pneumatic foramen. This latter is on the under side 
of the head of the bone, snrrounded on its upper, proximal, and lower 
aspects by a firm bony wall, the lower and proximal parts of which are 
continuous with the smooth and otherwise unbroken surface of the ex- 
panded and palmar side of the head. 
The pneumatic fossa thus formed is deep, having at its bottom the 
foramen alluded to. Quite often the aperture is multiple, and vast 
differences in size exist, being very large in some individuals, nearly 
consuming the base of the fossa where it is found. From tbe lower 
boundary of the pneumatic enclosure another longitudinal line is seen 
on the proximal end of the shaft, limiting the anconal face of the trihe- 
dral end of the humerus in this’ direction. The palmar aspect of the 
head, broad and smooth, arches gradually inwards and towards the 
articular facet; it is also. slightly convex from above downwards, sup- 
posing the bone to be in situ and in its position of rest, as we do during 
the course of our description. 
The shaft of the humerus is subcompressed from within outwards, 
smooth, and, viewing it laterally, it is barely convex above, by virtue of 
the ends being bent slightly down; viewing it from above, we may say 
that it is almost straight. 
It retains its form until close under the expanded distal extremity, 
which is curved palmad. On the radial side of this end of the bone we 
find the transverse and convex elliptical trochlea below, for the sigmoid 
articulating depression of the ulna. This has inferiorly the quadrilat- 
eral internal condyle. 
The ulnar convexity is separated from the oblique tubercle for the ra- 
dius most effectually by a deep, well-marked, though narrow, notch. 
The oblique tubercle maintains its usual position as found on this bone 
in birds generally. 
