54 PROFESSOR OWEN ON THE 
‘The hypapophysis of the first of the three expands at its termination (Pl. XVI. fig. 1, 
hy), with the hinder angle bent back to coalesce with the front one of the next hypapo- 
physis, which is somewhat longer, and bent forward with a similar terminal expansion : 
a full elliptical space is intercepted by this terminal confluence of these hypapophyses 
(Pl. XVII. figs. 1 & 5, hy). Each vertebra shows an elliptical articular cavity (ib. figs. 
1 & 5, p, ps) for the head of the rib, near to the anterior articular surface; the long 
axis of this costal surface is directed from above obliquely downward and forward. The 
surface of the rib’s tubercle cuts obliquely the lower part of the free end of the dia- 
pophysis (Pl. XVI. fig. 1, d). 
The neural arch circumscribes a canal the anterior outlet of which (ib. fig. 1, 2) is 
oval with the small end downward, 5 lines in vertical, and 53 in transverse diameter: 
the sides of the neural canal slightly project inward above the lower third: the posterior 
outlet (Pl. XVII. fig. 4, 2) is more regularly elliptical in form, and rather narrower in 
proportion to its vertical diameter. The neurapophysis sends off from the outer and 
fore part of its base a stout process, which expands and divides into zygapophyses (PI. 
XVI. fig. 1, z) and diapophyses (ib. d); the articular surface of the former is of a 
full oval shape, flat, looking obliquely upward and inward; the diapophyses extend 
outward and a little backward: the articular surface for the tubercle of the rib is 
transversely elliptical and nearly flat. The hinder part of the neurapophysis expands 
into the postzygapophyses: these have coalesced with the praezygapophyses in the suc- 
ceeding vertebra (Pl. XVII. fig. 2, z), as has happened also between this and the third 
vertebra. In the last of the three vertebre the postzygapophyses are entire (ib. z3), 
and show very slightly concave, oval articular surfaces, looking obliquely downward and 
outward (ib. fig. 4, z). The conjugational foramina, continuously surrounded by bone, 
are a full ellipse, and large, the anterior one (ib. figs. 1 & 5, f) being 54 lines in vertical 
diameter; the second (ib. f') is somewhat less: these foramina are also rather larger in 
one of the specimens than in the other. The length of the three coalesced dorsals is the 
same in both, viz. 2 inches 3 lines. The neural spines have run together into a con- 
tinuous ridge in fig. 1, ms; in fig. 5 the summit is broken off in both, leaving only the 
anterior angle of the foremost entire; in both this inclines forward; the hinder border 
of the third vertebra (fig. 1, ns) has the same vertical parallel as the back part of the 
centrum. ‘The anterior margin of the base of the spine shows a rough surface for the 
attachment of ligament (Pl. XVI. fig. 1, ms). A small foramen behind the base of each 
of the coalesced zygapophyses (Pl. XVII. fig. 2, z z) leads to a canal descending to 
the neural one, and indicates superiorly the limits of the otherwise continuously ossified 
neural arches. 
In the series of detached vertebre, one (Pl. XVII. fig. 6 & 7) indicates by its neural 
spie and hypapophysis a position at the base of the neck. The centrum is barely an 
inch in length ; its anterior surface (ib. fig. 7, c) is narrow vertically, broad transversely ; 
both fore and hind surfaces indicate freedom and extent of flexure. The hypapophysis 
