1869. | HUXLEY—TRIASSIC DINOSAURIA. 47 
physes of the antecedent vertebra laterally. The postzygapophyses 
of the first vertebra are completely ankylosed with those of the second; 
and those of the second seem to have been similarly united with those 
of the third. The centrum of the first vertebra, on the other hand, 
is not absolutely fused with that of the second, the separation being 
everywhere traceable; and the union between the centra of the 
second and third vertebrz seems to have been still morelax. Each 
neural arch is connected only with its own centrum, and the inter- 
vertebral foramen lies over the posterior moiety of each centrum. 
A strong, prismatic sacral rib with a triangular section, only the 
proximal end of which remains, springs from the junction of the 
centrum with the neural arch on each side, in the first vertebra, and 
appears to have been directed perpendicularly outwards. The se- 
cond vertebra seems to have possessed a similar rib, which, how- 
ever, springs rather further back from the anterior edge of the arch. 
The third vertebra also possesses a strong rib, the root of which 
occupies the middle of the arch. The contour of the broken end of 
the rib is more nearly four-sided. The anterior and posterior faces 
are concave from above downwards, and are directed obliquely, 
the anterior upwards, and the posterior downwards. The centrum 
of the anterior vertebra is 1-6 inch long, that of the third 1-75 inch; 
but the difference may be the result of the crushing of the vertebra, 
which are a good deal distorted. The height of the centrum seems 
to have been about 1°3 inch, the width about 1-1 inch. 
Mr. Kirshaw has sent me two centra of vertebrae, which may very 
well have belonged to the same animal as the sacrum. One of 
these is almost undistorted, and belongs to the dorsal region. It is 
1-6 inch long; and the better-preserved articular surface is 1:55 inch 
high, while its greatest width is rather less than ] inch. The sur- 
face is very slightly concave, and is perpendicular to the axis of 
the centrum. The centrum is much constricted, so as to be not 
more than 0:6 inch wide in the middle; and, as in the other ver- 
tebre, the floor of the neural canal sinks rapidly from each end 
towards the middle of the centrum. Some of the vertebrae from the 
Bristol conglomerate bear an extraordinarily close resemblance to 
these. 
The fragmentary vertebra described and figured by Professor 
Owen as belonging to Labyrinthodon pachygnathus has the same 
general characters as those now described. The vertebra ascribed 
to Labyrinthodon leptognathus, on the other hand, appears to have 
belonged to some other reptile. 
The remarkable ilium ascribed to Labyrinthodon pachygnathus 
(1. c. pl. 45. figs. 16, 17) is also a reptilian bone, intermediate in its 
characters between the ilium of a Teleosaurian and that of a Lizard. 
It is very similar to an ilium from the Keuper described and figured 
by Von Meyer (‘ Paleontographica,’ Bd. vii. pl. 41), and ascribed by 
him to Belodon. I propose to discuss the nature and signification of 
this remarkable bone in another communication. 
I have no direct evidence of the presence of Dinosauria in the 
Elgin sandstones; but ample proof is in my possession that the 
