SHUFELDT.] OSTEOLOGY OF TH& EREMOPHILA. 647 
ulna is likewise articular, being vertically cleft and curved downwards. 
Anconad it develops a rough eminence, and above a depression for the 
fan-like expansion of the radius. This end, as in the majority of the 
class, articulates with the three carpal bones and the radius above. 
The humerus measures 2.4 centimetres, the ulna 3 centimetres, and the 
radius 2.7 centimetres; so that when the bones are placed in situ and 
the wing closed, the anti-brachium projects beyond the brachium about 
5 millimetres. The bones of the forearm, though hollow, are apparently 
non-pneumatic, as is the case with the carpals and long bones of the 
manus. 
As in the great majority of the class, the bird-wrist is composed of 
the two free carpals and the os magnum, which is confluent with the 
proximal extremity of the second metacarpal. 
The superior and smaller carpal is the scaphoid, here an irregularly 
shaped bonelet, introduced among the cubitus, the radius, and the conflu- 
ent osmagnum, with a distal articular face for the latter and two proximal 
ones for the trochlez of the anti-brachium. Between thescaphoid and the 
cuneiform, the other free and inferior carpal, there exists an interspace, 
where the ulna meets the os magnum. 
The cuneiform has an elongated facet on its outer aspect for the ulna, 
and two articular processes that grasp the metacarpal below—an arrange- 
ment that admirably meets the action required of the avian wrist. 
The last carpal merely constitutes the trochlear head of the confluent 
metacarpals; by a gentle and backward sweep its general surface is di- 
rected inwards. 
The composition of the metacarpal bone of this bird does not deviate 
from the general rule, as applied to the class, in any important particu- 
lar. The three long bones comprising it are firmly anchylosed together 
and bear the fingers. The shortest and first metacarpal, obliquely fused 
with the anterior and upper end of the second, supports afree and pointed 
index digit. The second, or medius, supports, first in order below, a 
phalanx peculiar to birds, that is at once recognized by its expanded 
posterior border. It is here deeply concave on its inner surface, which 
concavity is partially divided by a feeble transverse line. 
The blade of this bone is quite thin in some birds, even the general 
surface is sometimes absorbed, leaving nothing but the rounded and 
limital borders, as in Larus delawarensis and others. 
The neck of this bone is but moderately constricted between the blade 
and articular facet for the metacarpal to which it belongs. It bears be- 
low another, and the smallest, phalanx of the hand, a little, free, sharp- 
pointed and compressed finger, that completes the skeletal bird-arm dis- 
tally, being the ultimate segment. 
The third metacarpal, termed annularis, a slender, ribbon-like bone, 
fast above and below to medius, and extending slightly beyond it, also 
articulates distally with another free phalanx, of the general character 
as the index digit and the ultimate joint of the mid-metacarpal, although 
it is longer than either of them. Measuring along the anterior aspect, 
from the summit of mid-metacarpal to the point of the last phalanx, we 
find the manus in Hremophila to average 2.6 centimetres. 
This, the pectoral limb, as we have endeavored to picture it in this 
Lark, with its brachium, anti-brachium, and pinion in proportionate 
equipoise as to length of segments, with its various bones smooth, 
straight, and devoid of those evidences of being acted upon by powerful 
muscles, would require but a glance from the student of avian skeletol- 
ogy to pronounce it as belonging to a bird possessed of a flight barely 
mediocral in rapidity and power.. 
