28 
Osteological Studies of the Sub/amity A rdein as. 
Five years ago, when this paper was first written, I had but 
few skeletons of herons in my possession, all belonging to my pri¬ 
vate cabinet; since then, as I have elsewhere siated (in Part I), I 
have been permitted to examine a number of herondine skulls in 
the collection of Mr. Lucas, as well as a few belonging to the 
U. S. National Museum, all of which material has been of the 
greatest service in the present connection, and for the use of which 
my thanks are again tendered. 
It was these additional facilities for comparison that induced 
me to depart from my original intention, and enabled me at the 
same time to present a more complete synopsis of the comparable 
characters in the skeletons of our Ardeines , the same being here¬ 
with subjoined. 
Synoptical and Comparative Review of the chief Osteological Char¬ 
acters of certain species of North American Ardeines . , 
1. In all Herons of this group the superior osseous mandible 
is of a subpyramidal form, with its base merging into the skull 
and its apex at the tip of the beak ; and with three sides, the an¬ 
gle of the culmen being rounded off, the other two angles cultrate. 
In length it is a little less than twice as long as the remainder of 
the skull, being notably shorter in some of the Night Herons than 
it is in the genus Ardea. 
2. Osseous internasal septum very incomplete or altogether 
absent. 
3. All are acutely holorhinal birds. 
4. All have (in the dried skull) a moderate movement at the 
cranio-facial hinge ; best marked in the Night Herons. 
5. Ethmoid much swelled ; broad and spreading under the 
frontal region ; and truncated transversely in front, just posterior 
to the line of the cranio-facial hinge. 
6. Pars plana very feebly developed both in A?'dea and the 
Night Herons. Fails to meet the inferior and backward extend¬ 
ing process of the lacrymal of the same side. 
7. Very large, spongy maxillo-palatines, lofty and parallel to 
each other in the rhinal chamber, attached to nasals and premax¬ 
illary by bony union. In some specimens they may come in con¬ 
tact with each other mesially, or they may have the anterior part 
of the vomer resting upon their hinder ends. In Ardea they are 
nearly all of a bony spongy tissue, (cancellous). In Nycticorax 
