40 
RECORDS OE THE AUSTRALIAN MUSEUM. 
Assuming this to be correct, one of the faces of the trihedral 
process, the dorsal, is flattened, or in the slightest degree convex ; 
the under, or ventro-lateral, being faintly concave, and the 
posterior flattened and to some extent truncate. The apex is 
sharp, acuter than any of the processes figured by Sir It. Owen.* 
but less generally cornute than the supra-temporal cores b of 
the head.f 
The second specimen only differs materially from the first in 
the antero-apical line losing much of its ridge-like character, 
and becoming obtusely rounded. Owing to the more extensive 
preservation of this part of the process, and the disintegration of 
the posterior lower portion, this horn-core presents the appearance 
of a greater obliquity than the other. The length of the antero- 
apical obtuse ridges is four inches ; the an tero-posterior diameter 
is four and a half inches ; the transverse diameter three inches ; 
and the height two and three-quarter inches. The lateral and 
posterior faces are flattened. The surface of both cores is pitted 
and veined by neuro- vascular markings. 
If, in the first place, it be admitted that these are osseous cores 
for the support of dermal appendages, their interpretation does 
not seem surrounded with much difficulty. We are not acquainted 
with any Australian extinct animal, other than Meiolania , , possess- 
ing such exoskeletal outgrowths : and as we know only the skull, 
part of the tail-sheath, and a few individual bones of this genus, 
it is but logical to compare these bony processes with those of 
either one or other of the former. 
The horn-cores of the skull in Meiolania are either depressed 
mammillary (the supra-parietal and other smaller pairs), or acutely 
conical and cornute (the supra-temporal pair). Those of the tail- 
sheath, on the other hand, arranged in four parallel rows, two 
dorsal and two lateral, are “ massive conical processes, like the 
horn-cores of the skull, but of larger size, being broader and 
thicker in proportion to their length, and rather more robust at 
the apex the upper or dorsal pair being the largest and longest. 
The appearance of our fossils would indicate that they are from 
the rings of a tail-sheath, although on comparison with a good 
plaster reproduction of M. Owenii , they are seen to be more 
strictly trihedral, and their apices more regularly conical and 
sharper than in the former. The difference in shape may perhaps 
be more apparent than real, and arise in a great measure from 
their detached condition and imperfect peripheries ; although at 
present their bases are wider in proportion to the height than in 
# Phil. Trans., elxxi., t. 37 j Ibid , clxxii, t. 65. 
fPhil. Trans., elxxi., t. 37, f. 1, b' 
J Phil. Trans., clxxii., p. 547. 
