i3 
Osteological Studies of the Subfamily Ardeinoe. 
valley, which appears all the deeper from the great prominence 
attained by the crest in question. 
The radial crest is, on the other hand quite low, and not 
unusually developed. It extends down the .shaft only to the 
point where the latter commences to assume the cylindical form. 
On the palmar aspect of the proximal end of the humerus we 
have a well defined trench extending across the bone, just behind 
the ulnar crest and glenoid head. Another fainter one, though 
pretty well marked in the direction of the shaft, marks out the 
boundaries of a convex, sub-oval and flattened space, on the 
lowermost side of the palmar aspect of the proximal end of the 
bone, which is present in some form or another in this place on 
the humerus, in a number of the class. 
The shaft for the greater share of its length is cylindrical 
and smooth ; the sigmoid curves it presents in the majority of 
birds are here well marked. The distal extremity is dilated in the 
same plane nearly with the proximal end, to give space for the 
guidance of muscular tendons on the anconal side, which there 
pass over grooves marking the bone, as well as affording the neces¬ 
sary breadth to support the ulnar and radial tubercles on the palmar 
side. Above the latter is seen a long, subelliptical depression, 
running obliquely up from this dilated portion to a point where 
the shaft begins to assume the cylindrical form. 
Albatrosses and some other seabirds, as the Gulls, Auks, and 
Petrels, the humerus presents a notable “ ecto-condyloid ” process 
on the radial side, near its distal extremity (Owen). No trace of 
such a process as this is found among the herons. So far as I have 
examined them, I found it, however, on the humerus in the locality 
just referred to, of Numenius longirostris , of Hcematopus , and of 
other limicoline birds, and presented a figure of the bone showing 
it in the first mentioned form, in my osteology of the Tong-billed 
Curlew which appeared in the nineteenth volume of th Journal of 
Anatomy and Physiology (Oct., 1884). 
The radius is a non-pneumatic bone, and like all bones of 
this character, in the ordinarily prepared skeleton becomes yellow, 
dark and greasy, owing to the oily constituents of the contents of 
the shaft gradually oozing through its walls. 
This bone, in common with its companion in the anti-brach- 
ium, is considerably longer than the humerus. From proximal 
to distal extremity its shaft is much bowed in the palmar direction. 
