34 CASE. [VoL. XIV. 
arch is broad and rugose. There is a triangular articular face 
at the base of the arch on the anterior portion of the centrum. 
The description of the vertebrae from Pvofostega given by 
Cope (32) is here quoted to show their general nature. 
He says of the vertebrae: “These have been recognized 
chiefly by their neural arches, which are separate. They are 
in form something like an X, the extremities of the limbs car- 
rying the zygapophysial surfaces. The only point of contact 
with the centrum is a wide process, which stands beneath the 
anterior zygapophyses, and spreads out foot-like obliquely for- 
ward and outward to beyond the line of the anterior margin. 
Its surface extends nowhere posterior to the surface of the 
zygapophysis above it, but a little farther inward. Its outer 
margin rises ridge-like to the under side of the neural arch, and 
each one, forming a semicircle, forms the boundary of the 
neural, and turning outward, forms the zzzer boundary of 
the posterior or down-looking zygapophysis. The space be- 
tween these apophyses is roofed over so as to produce a shallow 
zygantrum, which, however, only seems to roof over the deep 
emargination of the neural arch of the vertebra immediately 
following. The anterior zygapophyses are often broken away, 
so that the neurapophysial supports look like the missing pair, 
when the difficulty ensues that both pairs look downward. The 
top of the neural arch is, in two cases, broad and flat; in two 
others there is an obtuse keel. 
«The centra, apart from their arches, are puzzling bodies, 
especially since in the present case they are somewhat flattened 
by pressure. They differ materially in size, one of them being 
twice the size of the others. The smaller ones are of the ball- 
and-socket type, and have a deep longitudinal groove on each 
side. The thickened portion of the centrum forms the inferior 
boundary of the pit groove, while a thinner portion, possibly a 
diapophysis, limits it above. It is, however, thin, and has no 
great length. There is no sign of chevron bones and articula- 
tion, so that these vertebrae may have been cervical. Their 
bodies are, however, shorter and wider than in those vertebrae 
of any known tortoise. A groove on the upper surface repre- 
sents the neural canal, while a flat area on each side in front 
