BHUFELDT.} OSTEOLOGY OF THE EREMOPHILA. 643 
extend from each vertebra, downwards and outwards, decreasing in 
width from before backwards; in fact, each vertebra in the coccygeal 
series becomes more and more rudimentary as we proceed in that di- 
rection. 
The articular facettes upon the centra start reniform, to terminate 
almost circular in the last vertebra; and the zygapophysial processes 
are exceedingly elementary in character. 
The pygostyle is parallelogramic in outline, articulating with the ulti- 
mnate coccygeal vertebra by an unperforated cup-shaped depression, at 
the middle of its long anterior side. The edge of the bone above this 
point rests on the posterior border of the neural spine of the last caudal; 
below it is free. 
The superior angle is more or less produced, and the posterior corner 
of the parallelogram is expanded laterally; this expansion is highly 
developed in many birds, as in Colaptes mexicanus and other members 
of the family Picide. The caudal vertebre are non- pneumatic in our 
present subject, whereas in the pelvis we find these foramina in their 
usual localities. 
The scapular arch—(Pl. IV, Figs. 22, 30, 32, 33, and 34).—This arch 
is very strong and perfect in this bird, as it is among the Oscines gen- 
erally. 
The bones can be easily separated from each other by maceration, 
though during life they are remarkably well strapped together and to 
the sternum by their numerous ligaments. 
The scapula lies along the dorsum in its usual position over the dor- 
sal pleurapophyses, parallel with the vertebre, with its posterior point 
touching the fifth one in the vast majority of the specimens. 
Certain bones in all skeletons force upon us their resemblance to fa- 
mniliar objects, and we know many of them have received their distinct- 
ive appellations through such likeness; more particularly is this the 
case in the skeleton of man, where the bone we are describing is fre- 
quently termed the shoulder-blade, but how much more blade-like is the 
scapula in this Lark and many other birds, as far as shape is concerned. 
It is truly a miniature bony cimeter in Hremophila. This is not true for 
scapule of all birds, however, for no one would ever be struck by such 
a resemblance while regarding the J-shaped scapula of Colaptes meat- 
canus, or the straight, almost square-cut bone in some of our natatorial 
birds. 
In the Horned Lark the scapula is pointed and obliquely truncate be- 
hind for more than a third of its slightly dilated posterior portion, on 
the side towards the vertebre. 
The outer border is reénforced by a rounded ridge for nearly its en- 
tire length, while the inner is quite sharp. 
The blade becomes stouter and subcompressed as we near the gle- 
noidal process; this broad tuberosity extends downwards, forwards, and 
outwards, and is crowned on its entire summit by a curved, subcircular, 
articular facet, that supplies rather more than one-third of the glenoid 
cavity for the head of the os humeri. 
The acromial process is bifurcated, and the clavicular head rests in the 
fork. The larger bifurcation is the lower, and both rest against the 
coracoid, on the inside and just below the head, creating the usual 
. Scapulo- coracoid foramen, which in this case is not very extensive. 
The scapula is pneumatic, and the foramina are to be found at the ex- 
tremity of the larger bifurcation of the acromial process, and in the 
notch between the two. 
The coracoid can boast of a very fair subcylindrical shaft between its 
