598 PROF, H. G. SEELEY ON THE DINOSAURIA OF 
are not clearly defined; a broad median concavity on the basal sur- 
face of the centrum may indicate that they were separate. This 
chevron region is 1,3, inch wide, and not more than ;4, inch long ; 
it is oblique, looking downward and backward. 
The sides of the centrum are somewhat flattened, are obliquely 
inclined, and converge towards the base, which is about an inch 
wide, and defined chiefly by the rounded ridges in the line of the 
chevron bones. The sides are slightly convex from above down- 
ward, and moderately concave from front to back. 
The transverse processes have their superior surfaces on a level 
with the base of the neural canal. At their union with the centrum 
they expand in every direction so as to haye a nearly circular base 
and to spread to the width of the centrum. As preserved, the pro- 
cess is about 1,4, inch long. It is compressed from above down- 
ward, being twice as wide as deep, and tapers a little outward, 
being 54 inch wide at the end. The posterior margin is more curved 
than the anterior margin; and while the superior surface is more 
flattened from side to side, the inferior surface is the more convex. 
The neural canal is vertically ovate, about ;8 inch high and more 
than 55, inch wide. 
The neural arch is moderate, with the neurapophyses compressed 
from side to side and directed forward, so that the prezygapophyses 
project anteriorly to the front of the centrum ; these processes were 
strong and subcylindrical ; their articular ends appear to have been 
about 1,8, inch apart anteriorly, and to have converged backward 
in a A-shape, being deeply divided in front. Above the zyga- 
pophyses, of which the posterior are not preserved, the neural spine 
is directed obliquely backward, and becomes more compressed 
from side to side; it is fractured at less than 2 inches above the 
base of the neural canal, where it appears to be ;5, inch long and 
less than =, inch wide, and of an almond-outline in section, being 
sharper in front than behind. 
Middle Caudal Vertebre.—Centrum about 14 inch long, with the 
articular ends subcircular, wider than deep, the anterior apparently 
the larger, but both about 1,2, inch deep and wide (fig. 3). There 
is a rather deep, narrow, concave, median groove (see fig. 3, 6) on 
the base of the centrum, about 3, inch wide, which does not enlarge 
towards the ends. The sides are made subangular by two imperfect 
lateral ridges (see fig. 3, a), of which the lower is but slightly de- 
veloped, and the upper one has in the middle the rudiment of a 
transverse process. The neural arch is compressed from side to 
side, prolonged backward beyond the centrum into a neural spine 
with parallel superior and inferior margins, more than 3 inch deep 
and rising 1,2, inch above the base of the centrum, and compressed 
posteriorly from side to side. Anteriorly it is prolonged into two 
stout zygapophyses, which, as preserved, do not extend in front of 
the centrum. 
The latest caudal vertebra preserved is in the Museum of Practi- 
cal Geology. It has the centrum 14} inch long, and the neural 
arch rather shorter. The articular ends of the centrum are sub- 
