THE CAMBRIDGE GREENSAND. 629 
tebre being of relatively much greater length, and distinguished by 
carrying the neural canal in a deep groove in the centrum. The 
remaining three vertebre present the characters of Acanthopholis, 
and may well have belonged to the same animal as the preceding 
five bones. 
Dorsal Vertebre.—The two dorsal vertebre present the charac- 
ters already described in dorsals of Acanthopholis and Anoplosaurus, 
but have the articular faces of the centrums more deeply concave 
than in any form hitherto described. It may therefore be enough 
to say that the dorsal measurement in both is a little greater than 
the visceral measurement ; that the aspect is Teleosaurian, slightly 
compressed, and well rounded on the base. There are several small 
nutritive foramina in the middle of the side. The neural canal is 
a long groove with parallel sides, and its width is less than the 
width of the lateral surfaces from which the pedicle for the neural 
arch is broken away. ‘The better-preserved and slightly longer 
of the two vertebre is 147 inch in extreme length, has the posterior 
articular face 14 inch deep and rather narrower, while the anterior 
articular face is nearly circular, with the measurement of 14 inch. 
The greatest compression of the centrum from side to side, where its 
transverse measurement is | inch, is below the neural canal. 
Postdorsal.—A bone which I am disposed to regard as a last 
lumbar or, more probably, postsacral vertebra, is distinguished by 
a large neural canal, and a centrum which is oblong and defined 
by six sides. The body of the vertebra is 1,7, inch long, with 
a flattened base, flattened sides, and subquadrate articular ends. 
The anterior end, as preserved, is 1,2; inch deep and more than 12 
inch wide. The posterior face is somewhat smaller; both are concave 
surfaces, with a somewhat large obscure central boss. The base at 
each end is 1,2, inch wide, and about 5%, inch wide in the middle. 
There is no indication of its lateral ridges being connected with 
facets for chevron bones; the sides are similarly gently concave 
from back to front, and show a thickened mass at the base of the 
neural arch, as though a slight transverse process might have there 
originated, or a facet existed for a small osseous attachment. It 
is impossible from the fractured fragments of the pedicle of the 
neural arch to judge what the characters of that portion of the 
vertebra were. The least width of the neural canal in the middle is 
42% inch. 
The early caudal vertebra is in good preservation and shows 
unusual characters. The neural arch is anchylosed to the centrum, 
the short transverse processes are well indicated, and the facets for 
the cheyron bones are unusually large for this genus, and divided 
from each other. The centrum is 13} inch long dorsally, 14 inch 
long ventrally. The transverse processes are short, vertically com- 
pressed, rather oblique, and placed posteriorly on the upper third of the 
centrum ; they measure from front to back about 55, inch at their 
bases. Below these transverse processes, the sides of the centrum, 
which are flattened, converge towards the visceral surface; but the 
base can only be defined at the articular ends by the width of the 
