SHUFELDT. | OSTEOLOGY OF THE EREMOPHILA. 639 
angle, but suddenly changing mind, proceeded directly upwards and 
backwards at an equal angle; hence the condition alluded to. 
When the first dorsal rib articulates with the hemal spine below by 
the intervention of a sternal rib, this latter bone is quite small and del- 
icate, averaging about 3 millimetres in length, and but slightly curved. 
The remaining dorsal hemapophyses become longer and more curved 
as we follow them backwards. They are all flattened from side to side, 
their lower extremities being abruptly twisted at right angles with their 
shafts, enlarged, and terminating in a flattened articular surface for the 
costal border of the sternum. These articular surfaces are dumb-bell 
shaped, 2. e., contracted in their middles. The upper ends of these sternal 
ribs are also enlarged and laterally flattened for articulation with the 
vertebral ribs. These latter enlarged ends are sometimes larger, some- 
times smaller, than the extremity of the pleurapophysis they meet. 
lf we accept as true the old vertebral theory of Oken, Goethe, and 
Owen, a theory that holds that the skull of all vertebrates is composed 
of three, four, or more modified vertebre, that these vertebre in evolut- 
ing from the very earliest forms in which a bony segmented column 
appeared, that during this evolution many metamorphoses took place 
in the skull, such as the restriction of the notochord to the first or oeci- 
pital vertebra, the mode of development of the elements themselves, 
whether by eartilage or membrane, and the appropriation by these 
‘cranial vertebrae” of bones that did not originally belong to them, that 
we cannot positively say what may become of the cranial extremity of 
the spinal column of Amphioxus, or some of the heemal arches in the hag 
and others, then we must recognize in the sternum of birds, developed 
as it may be, the confluent hemal spines of the dorsal series of ribs; 
and in it, in its maturity, .see one of the most interesting bones to con- 
template, it being one of the most diversified in form in the bird skeleton. 
Owen styled the type of this bone, as found in the Lark now under 
consideration, “‘cantorial” (Anat. and Phys. of Vert., Vol. II, p. 20). 
It is certainly typical of the suborder Oscines, as far as American orni- 
thology is concerned; good examples as testifying to this I have now 
before me, in the hzmal spines of Turdus migratorius, Ampelis garrulus, 
Mimus polyglottus, Lanius, and many others. 
In Hremophila the sternum is very light and delicate in structure; so 
thin is it in some individuals that we find deficiencies occurring, usually 
in the body, as foramina of no mean size (1.8 millimetres). Its outer 
surface, indeed the entire surface of the bone, has the appearance as if 
it were venated, the solid bony veins being thicker and more opaque 
than the general surface of the bone, and branching from the various 
borders. 
The carinais moderately well developed, measuring in the vertical line 
below the coracoidal groove 9 millimetres. Its inferior border, expanded 
behind, is rounded and somewhat thickened; this thickening disappears 
on the anterior border, which is sharper and continuous with a conspicu- 
ous crest on the front of the manubrium. 
The carinal angle, with an aperture of 70°, is quite prominent and 
produced anteriorly. Just within the anterior margin of the keel we 
find a rather prominent carinal ridge, its lower extremity brauching 
backwards, and by its ramifications taking part in the superficial vena- 
tion referred to above. The keel arises abruptly from the inferior and 
median angles formed by the sides of the body where they meet mesiad. 
The xiphoidal prolongation is profoundly notched once on each side. 
These notches have the outlines of isoceles triangles, with their angles 
rounded, and apices but a short distance from the costal borders. These 
