602 SHUFELDT—OSTEOLOGY OF THE WOODPECKERS.  [0ct.5, 
that indicate the boundary lines among the three bones that enter 
into its composition upon either side of the sacrum. Even at this 
age it is already strongly indicated that its sides are to be deep, its 
basin capacious, and its preacetabular portion comparatively nar- 
row (see Figs. 9 and 10). 
A rudimentary riblet may be suspended upon either side of the 
twelfth cervical vertebra, and a better developed pair occur on the 
thirteenth, while on the fourteenth cervical the pair of ribs, al- 
though freely suspended, possess well-marked epipleural or. unci- 
form appendages. 
These latter are very large on the fifteenth, sixteenth and seven- 
teenth pairs of ribs, small on the eighteenth, and entirely absent 
on the nineteenth, as they also are on the pair of sacral pleura- 
pophyses. The four pairs of true dorsal ribs articulate with the 
sternum through the intervention of sternal or costal ribs, and 
the anterior pair of these latter are very conspicuous from their 
unusual bigness-—not so much so in this nestling, however, as they 
are in the full-grown Co/af/es, and still more so in adult individuals 
of other species of our Pic? Regarding the haemapophyses of 
the sternal ribs, or rather pair of ribs, we observe that they do not 
reach so far as the costal border of the sternum upon either side. 
At this age the sternum is but subdeveloped, showing but imper- 
fectly the pair of notches on either side behind, while the carina is 
shallow and the manubrial process not complete. 
With respect to the shoulder-girdle in this young Red-shafted 
Woodpecker, I find that the hypocleidium is absent from the os 
furcula, and that this bone has its upper ends pointed. In front of 
either of these points we observe a flat, triangular piece of bone of 
some considerable size that lies against the head of the coracoid 
and the anterior extremity of the scapula of the same side. This 
piece ultimately fuses with the end of the clavicle, and thus either 
end gets to wear the form of the bone as we find it in the adult 
Colaptes. Probably this method of formation is common to all of 
our species of Woodpeckers. 
The distal ends of the scapule are slightly expanded and 
rounded, and as yet but faintly suggest the peculiar form they take 
on in fully matured individuals. 
Nestlings very imperfectly show the pneumaticity that eventually 
comes to so generally obtain in the pectoral extremity of the old 
birds of this species and some other /’c:—for representatives of 
