330 SHUFELDT. [Vou. II. 
pressed in the antero-posterior direction, and curved somewhat 
upwards. Os furcula typifies the U-shape form of the bone, and 
has in al] Lzmzcole, that the writer has ever studied, the merest 
apology for a hypocleidium, below. Its limbs are of nearly 
uniform calibre throughout, being slightly heavier above than 
below, and-moderately compressed transversely for their entire 
lengths. Their heads, that is, the free ends of the clavicular 
limbs, are much elongated, and when articulated zz sztu, reach 
far back to the heads of the scapulaz. Viewed upon direct lat- 
eral aspect, it will be noticed that the os furcula is very con- 
siderably, though gracefully, curved in the antero-posterior 
direction, the convexity of the curvature being to the front. 
In Hematopus the shaft of a coracoid is pierced by a small 
oval foramen, from before, backwards, and just below the scap- 
ular process, that does not occur in either the Surf-bird or among 
Turnstones. 
Now, aside from the exceptions of this foramen, and differen- 
ces as to the method of articulation of the coracoids with the 
sternum, already alluded to, and finally, the mere matter of size, 
—the description of the shoulder girdle here rendered for 
Aphriza, will apply almost equally well to the shoulder girdles of 
the Zvinge@, the Turnstones, and the Plovers, and no doubt to 
many other Shore Birds. Were we to depend for characters, 
upon which to base distinctive differences, on the shoulder gir- 
dle alone in Aphriza, Arenaria, and a true Plover of a correspond- 
ing size, we should surely be disappointed, for the bones of this 
arch do not offer them in the genera enumerated. 
OF THE APPENDICULAR SKELETON. 
The Pectoral Limb. — The majority of the bones of this part 
of the skeleton in Aphriza are shown by my drawings in the 
Plate, as already stated above. The corresponding parts for 
Hlematopus and Plovers have been given in other connections. 
It will be seen that in the humerus of our Surf-bird, both 
“radial crest’ and “ulnar tuberosity”’ are strikingly well devel- 
oped, while the articular humeral head between them is rather 
small (Figs. 18 and 19). The pneumatic fossa is an extensive 
excavation, although the bone itself is not pneumatic. As to 
the shaft, it shows but little curvature, is smooth, and subcylin- 
drical in form. At the distal extremity of the bone, a conspicu- 
