2 4 
Osteological Studies of the Sub-Family Ardcincc. 
of the xiphoidal process, of which we also give a good side view. 
As a whole, the costal process is triangular, with its apex at 
the summit of the bone. 
Seen directly from above, the asymmetry of the two sides of 
the anterior border again becomes apparent, due to the method of 
articulation of the coracoids. A rounded notch exists in the me¬ 
dian line, flanked by a long facet on the right of it, and one, only 
half the size on the left. The manubrium is now seen to be tri¬ 
angular, with its surface flat and smooth. 
Well within the anterior boundary of the body of the ster¬ 
num, upon this superior aspect of the bone, we observe a single 
elliptical foramen of some size, situate in the median line, as is its 
major axis. This leads to caviries in the thickened part of the 
front of the carina, already alluded to in a paragraph above. 
From anterior border to xiphoidal extremity, and from sum¬ 
mit of costal process to summit of costal process this sternum is 
one general, and by no means shallow, concavity. There are no 
interruptions of surface, and all these parts enter into the confor¬ 
mation of the basin. 
For the most part it is smooth, and it is only in front that the 
surface seems to be roughened by some peculiar little granula¬ 
tions. Fig. 9, being a direct anterior view of the sternum of this 
Heron, the decussation of the coracoidal grooves is now best seen. 
The right one, (the left in the drawing) being the lower anteriorly, 
and running out over the top of the manubrium, while the left 
one, being the higher, crossing it in front. 
So far as I have examined, this is the method of decussation 
in each instance, i. e ., the right hand groove being the one that 
passes over the superior manubrial surface. 
It is just possible that this crossing of the coracoids may have 
arisen in the habit of the ancestors of the present Herons, of pass¬ 
ing constantly through very narrow places, as dense cane-brakes, 
or such other growths of analagous character, where they probably 
resorted, and spent the major part of their time. There would un¬ 
doubtedly be an effort made many times a day to compress the 
body and diminish its general bulk in a transverse direction, in 
such situations. Moreover, the coracoids (if arranged as in most 
birds) would constitute the principal obstruction to such com¬ 
pression; and it certainly lessens the width of the bird’s body to 
have them crossed as they are in the Herons. If we commence 
