14 
Osteological Studies of the Sub-Family Ardeinez. 
lofty porous plates, which being produced forwards meet the inner 
sides of the nasals and the premaxillary to fuse with them. In 
Nycticorax these hinder moieties have a thin outer layer of com¬ 
pact bone tissue covering them which more or less masks their 
spongy nature. 
This Heron has about the same relations existing among the 
palatines, the vomer, the rostrum of the sphenoid and the bones 
just described, as we find them in Ardea. 
In both, too, we find that the median surfaces of the upper 
part of the inner carination of the posterior third of the palatines 
is closely applied to each other, so closely in fact that in dried 
skulls one has to resort to the knife to separate them before we 
are assured that direct union has not taken place, as we find it in 
the Pelicans, Gannets and others, where the entire median surface 
of the inner carinal plates fuse to form one descending keel in the 
middle line. 
My specimen of the immature Yellow-crowned Night Heron, 
shows this union to be of so firm a nature, that it would not sur¬ 
prise me in the least to find in an old adult of this species, that 
perfect union had taken place between the parts of these inner 
keels of the palatines that come in contact behind. There is an 
excellent figure of the base of the posterior half of the skull of 
Ardea cinerea in Professor Huxle} T ’s memoir upon the classifica¬ 
tion of Birds in the Proceedings of the Zoological Society for 1867. 
Fig. 19, page 457. 
It agrees in every detail with the 
skulls of other true Ardea that I have 
before me, or have examined elsewhere. 
A pterygoid of the Blue Heron is a 
straight, stout bone, feebly crested on 
its upper side, while its inner aspect is 
grooved for its entire length. Both 
ends are dilated, the anterior one to 
receive the palatine head of the cor¬ 
responding side ; the other to articulate 
with the quadrate. Above this latter 
extremity a projection is developed 
on the outer side of which a large pneumatic foramen is seen, 
which is double in some specimens. This bone is devoid of anv 
sign of a process at the usual site where one usually developes to 
Fig. 5. Posterior view of the 
skull of A i dea herodias. Mandible 
removed. Same specimen as in 
former figures ; life size from na¬ 
ture. 
