26 
Osteological Studies of the Sub-Family Ardeince. 
toral arch. At the lower and inner angles of the coracoids, the 
dotted line indicates the amount of decussation of these bones when 
in situ in their grooves on the sternum. In A. candidissima the 
sternum differs from that bone in Ardea herodius , as I have de¬ 
scribed it above, in only the most insignificant minor details, 
indeed, in all essential particulars, it is the veriest minature of the 
latter bone. 
With Nycticorax, although the principal features are still there, 
of a Heron’s sternum, yet a comparison of Figs. 8 and 32 will show 
that the bone has departed somewhat from the type form as seen 
in Ardea. The keel is comparatively much deeper in front and 
slopes up far more rapidly behind ; the manubrium bears a lat¬ 
erally compressed plate on its anterior extremity, which is as long 
as the part which corresponds to the triangular portion in Ardea . 
Finally, the main pneumatic foramen, over the keel anteriorly, 
is very much larger. This may contract more, however, in speci¬ 
mens other than the one I have in hand, and in any event is a 
character of very trivial importance. 
