Osteological Studies of the Sub-Family Ardebits. 
small osseous cerato-hyal, on either side, embedded in the carti¬ 
lage of the second visceral arch. 
The first basibranchial is compressed from side to side in the 
Ardeince generally, with the posterior aspect of the hinder end, 
fashioned to articulate with the anterior heads of the cerato- 
branchials, and the head of a slender, styliform second basi-bran- 
chial of no great length, which rides above them in the median 
line. Each cerato-branchial is a long delicate rod of bone, in old 
individuals often attaining a length of 5.8 c. m., while the epi- 
branchials rarely exceed a centimetre and a half, are very slight, 
and have their hinder ends prolonged by needle-like tips of carti¬ 
lage, a condition which also obtains with the end of the second 
basibranchial or urohyal. 
A specimen of the Snowy Egret before me has the bony parts 
of the ear so well preserved that I am enabled to see the elliptical 
stapedial plate, and the delicate bony rod of the mediostapedial 
pait of the apparatus. The scleroial plates of the e}^e are elon¬ 
gated and rather narrow, they average from thirteen to sixteen in 
Ardea herodias. 
Before entering upon the remainder of the axial skeleton, I 
will take this opportunity to further say that the tracheal rings 
also ossify as in other birds. Comparatively, the tube seems to 
be of small calibre, and I think one would rather be led to look 
Tor a larger wind-pipe in so big a bird. 
Of the Vertebral Column; Ribs , (Figs. 25, 26 and 27.) In 
the Great Blue Heron the atlas is not large, when taken in com¬ 
parison with the size attained by other vertebras in the column, as 
for instance the nineteenth. Its cup for the condyle is notched 
above, and on either side of the neural arch above the usual blunt 
processes are thrown backwards (Fig. 25). 
The axis of this bird is a very irregular bone, and a difficult 
one to describe without resorting to tedious detail. For this 
reason I have added to my illustrations a figure presenting the ap¬ 
pearance of this bone on direct lateral view. It will be seen that 
that odontoid process” is quite large, being perfectly flat above 
and convex below. The centrum is deep ; thinned in its centre 
by the laterial concavites, beneath which, its lower margin is car¬ 
ried by a gentle curve from the articular surface at one end to the 
articular surface at the other. A11 elongated neural crest adds 
another curvature . to the bone above. The facets of the 
