ON A NEW SPECIES OF DICYNODON 139 
Chelonian, as will be obvious to any one who compares with these 
the corresponding sections of a Turtle’s mandible. The splenial 
bone, however, appears to extend to the symphysis, where it unites 
with its fellow. 
A fragmentary specimen of the skull of a small Décynodon Aur- 
vayt exhibits very beautifully marked impressions of the sclerotic 
bones in their natural arrangement. They form a zone 1,%; inch 
in diameter and $ an inch broad, which closely adapts itself to the 
bony circumference of the orbit. The sclerotic ring does not seem 
to have consisted of more than four or five ossicles. 
Bones of the Extremities of D. Murrayi—The only complete bone 
of the extremities which I have met with is a left humerus 
(Pl. XXIII. [Plate 9] fig. 3) 34% inches long, and not unlike 
that of a Monztor, except that it is proportionally wider at the 
articular ends and narrower in the middle. The deltoid crest is 
very large, with an almost semicircular free margin; and there is a 
deep posterior intercondyloid depression, as if for a large olecranon- 
process. 
Among the other remains, I found an extremely interesting frag- 
ment, consisting of the anterior part of the sacrum and the last dorsal 
or lumbar vertebra of Dicynodon Murrayt. 
The lumbar vertebra is biconcave ; its centrum measures ,’5ths of 
an inch antero-posteriorly and an inch transversely at its ends, while 
its centre is a little constricted. Superiorly it widens, and, uniting 
with the base of the neural arch, enters into a broad but short trans- 
verse process. The neural arch is broad, thick, and depressed,—the. 
neural canal not exceeding 3%;ths of an inch in diameter. A strong 
spinous process rises from it, and passes obliquely upwards and back- 
wards for an inch, to end in a truncated extremity. The first sacral 
vertebra is like the last lumbar; but the lateral enlargement, or 
rudimentary process, into which the neural arch and the centrum 
enter, unites suturally with the smaller end of a broad fan-shaped 
pleurapophysis, ?ths of an inch long, whose outer, vertically expanded, 
obliquely truncated end abuts against the inner surface of the ilium. 
The centrum of this vertebra is ths of an inch long, and it is 
concave anteriorly, flat posteriorly. The anterior articular face of 
the centrum of the next sacral vertebra is also flat, and is closely 
applied to, if not partially anchylosed with, the flat hinder face of the 
first. The upper parts both of it and of the next vertebra are much 
mutilated, but their pleurapophyses, similar to, but smaller than, those 
of the first sacral, are well preserved. The anterior faces of these 
