OF THE GREAT AUK, OR GARFOWL. 319 
lope postzygapophyses, above which are produced strong trihedral anapophyses ; there 
is a thick, obtusely ended, slightly recurved neural spine. 
The third cervical developes a compressed hypapophysis, slightly thickened and 
flattened below, from the hinder half of the centrum. From the sides of the base of 
the hypapophysis ridges diverge to parapophyses at the expanded fore part of the cen- 
trum, which is flat and triangular below; above each ridge the centrum is concave. 
Below the preezygapophysis a diapophysis coalesces with the short pleurapophysis, which 
circumscribes a vertebrarterial canal, the foremost of the series; above the postzygapo- 
physis there projects a trihedral anapophysis, less thick than that of the axis. A sharp 
horizontal ridge passes from the post- to the pre-zygapophysis, having a small vertical 
perforation behind; the neural spine is a little higher and less thick than that of the 
axis. The pleurapophysis projects as a slender, straight, obtuse process about 2} lines 
backward ; the intervening ‘‘ vertebrarterial ” canal is above a line in diameter. 
The fourth cervical (Pl. LI. figs. 4 & 5) resembles the third, but with shorter pleur- 
(pl), hyp- (hy), and an-apophyses (a), and with a rather shorter neural spine (ns). 
The vertical foramen in the interzygapophysial ridge (iz) is larger than in the third 
vertebra ; and below this a shorter ridge (r) passes to the base of the preezygapophysis (z). 
The posterior part of the neural arch is broader than the interior. 
In the fifth vertebra the interzygapophysial ridge is wanting ; but the one beneath is 
more developed. The anapophyses are reduced to ridges diverging from a stumpy 
neural spine to the postzygapophyses (z'). The diapophysis makes a backward pro- 
jection distinct from and above the pleurapophysis; there is an obtusely angular 
hypapophysial keel (Pl. LII. fig. 6, hy). 
In the sixth to the ninth cervicals the hypapophysis is obsolete, and the parapophysis 
(Pl. LI. fig. 1, p) sends a stumpy projection downward, increasing to the ninth, where 
it forms the side of a quasi-hemal canal ; the backward extension of the rib is reduced 
to a mere angle. On the broad depressed upper surface of the neural arch, both neural 
spine and anapophyses are represented by low ridges: the posterior part of the neural 
arch is narrower than the anterior. The diapophysis (ib. d) continues to project out- 
ward, and becomes bifurcate by a groove. 
In the tenth cervical the hypapophysis (ib. hy) suddenly reappears as a compressed 
quadrate plate from the whole under surface of the centrum, a little inclined forward, 
especially at the front angle. 
In the eleventh cervical there is a similar but rather shorter hypapophysial plate, and 
the pleurapophyses begin again to project backward, and the neural spine (ns) to reappear. 
In the twelfth cervical the hypapophysis is reduced to a short triangular process, and 
the neural spine forms a low thick knob; the pleurapophyses are still anchylosed as 
mere processes. 
In the thirteenth cervical they elongate, but are fixed; the hypapophysis is a mere 
ridge ; the parapophysés reappear as ridges; the diapophysis is widely cleft, and the 
