Oncological Studies of the Subfamily Ardeincs. 11 
These seven vertebrae in the Great Blue Heron are non-pneu¬ 
matic, and all but the last three entirely devoid of hypopophyses, 
and it may be absent on the first of these. 
The first five have broad flaring diapoplryses, which are 
entirely aborted in the last segment, and only barely apparent in 
the one that precedes it. 
In calibre, the neural canal is larger than we would be led to 
expect from the size of that tube as it appears in the last uro- 
sacral vertebra of the pelvis. 
The neural spines are bifid and sub-compressed, while the 
form of the anterior and posterior articular surfaces of the centra 
are transverse and flattened ellipses. 
Herons being birds with short, weak tails, composed of but a 
few feathers, we naturally find a correspondingly feebly developed 
pygostyle. 
In Ardea this bone has projecting forwards from its lower 
anterior angle a process nearly as long as half the bone itself. It 
represents the hypapophysis of the leading vertebra that was 
absorbed, to form, with probably several others, this compound 
bone. Very faint traces of another such a process may be seen 
marking its side further back, and above it, the barest hint of the 
centrum of the corresponding vertebra. For the rest, the pygo¬ 
style is an irregular, quadrilateral plate, less than a centimetre 
deep, and a little more than one long, measured on its longest 
diameter; with a round, thickened posterior margin, and upper 
and lower edges sharpened. A pit marks the flat anterior sur¬ 
face, which continues for a short distance into the substance of 
the bone, the neural canal of the caudal vertebrae. Other herons 
have the pygostyle rather differently fashioned from this, though 
in each instance the leading features are present. 
Of the Appendicular Skeleton. The Pectoral Limb :—Ardea 
herodias has a highly pneumatic humerus, which in the well prepared 
skeleton is a snowy-white, and for its size a wonderfully light 
bone. Nor is the pneumatic aperture of any great dimensions, it 
being a small sub-elliptical opening at the usual site for this orifice 
in birds. It differs somewhat, however, in lying in the same plane 
with the general humeral surface, below the ulnar crest, and not 
being situate at the base of a pneumatic fossa, in which several 
openings are usually seen leading to the hollow shaft of the bone. 
From radial to ulnar side the proximal dilation of the humerus 
