22 Osteological Studies of the Subfamily Ardeinee. 
of the shaft of the leg-bone to unite with it by ossification, for at 
least a third of this part of its length. 
Next in order we have to notice the tarso-meta/arsus. The 
differences that this segment of the lower extremity exhibits 
among the various herons, seem to be scarcely worth the mention. 
So I expect a description of the bone as it is found in Ardea 
herodias , will answer with sufficient exactness for the group. 
Different views of the tarso-metatarsus are shown in figures 
15, 16, 17 and 18 all drawn from an adult specimen of the Great 
Blue Heron. 
A very prominent tubercle occupies the anterior part of the 
superior surface of the proximal extremity. It stands between 
Fig. 33.—Left three-quartering view of furcula of Nycticorax violaceus , juv. 
Fig. 34.—Same view of the os furcula of Ardea candidissima. Both life size from nature. 
the two elliptical concavities intended, when articulated, for the 
condyles of the leg-bone. The margins surrounding the extremity 
are raised at the sides and sharpened. Posteriorly, we can also 
see from this view, the three processes composing the hypotarsus . 
Of these the innermost one projects the farthest backwards, as well 
as extending the greatest distance down the shaft. The outer¬ 
most one of the three is the smallest, being just about half the size, 
in height as in length of the innermost one. The middle one, 
falls between these two so far as its height is concerned, but it is 
as long as the innermost one (Figs. 17 and 18). 
In order to support this great, tendon-grooved hypotarsus, and 
broad articular surface, the shaft of the bone at this end is prop or- 
