8 
% 
Osteological Stiu ies of the Sub-Family Ardevice. 
Fig. 3. 
as Sul a, where there is no nostril pres¬ 
ent, and certainly in some cases vio¬ 
lently separates forms that in their 
general structure closely approach each 
other. 
We find upon lateral view in Ardea 
herodias, a subelliptical aperture, that 
is bounded anteriorly by the nasal, 
posteriorly by the lacrymal, and below 
by the maxillary. Through it can be 
seen the upper parts of the maxillo- 
palatines. The lacrymals in this Heron 
are very large bones (Fig. 2) ; the 
manner in which one articulates supe¬ 
riorly with the frontal and nasal has 
already been noted above. Anteriorly 
the bone has a regularly concave mar¬ 
gin, which bounds the aperture alluded 
to in the preceeding paragraph. Be¬ 
low, a lacrymal rests rather more than 
its anterior half upon the maxillary, 
then is slightly raised above it to pro¬ 
ject backwards as a process with a 
transversely notched tip. Above this 
part of the bone there is a constriction 
which divides it from the larger and 
upper portion. The surfaces are smooth 
and the bone is highly pneumatic, air 
gaining access to its interior through a 
large foramen on its mesial aspect. 
Owing to the broad frontals, the or¬ 
bital roof is very complete, while its 
outer periphery is sharp and thin. 
This roof is quite horizontal in Ardea , 
as we see it in the Gannets, but it is 
inclined to be tilted up in the Night 
Herons, and consequently not shield¬ 
ing the eye so completely from above. 
The ethmoid is an unusually thick 
Fig. 3. I.eft lateral view of the skull of Ardea herodias, same specimen as shown in 
Figs. 1 and 2. About three-fourths life size. 
