133 
greater or less extent, of its outer border. The middle phalanx 
is a still smaller compressed sub-quadrate bone. In the above 
features and in the depression of their articular surfaces both 
show a resemblance, on a small scale, to the proximal and middle 
segments of the fifth digit of the pes of Diprotodon. 
The ungual phalanges, of which four are represented, repeat, 
on a scale of about twice the size, the features of these elements 
in the wombat being considerably depressed and only slightly 
curved. 
ATLAS. 
{One specimen in which the tranverse processes have suffered 
considerable abrasion. | 
Transverse width, measured anterior to, but exclusive of, the 
transverse processes, 110 mm. 
Wombat, similarly measured 43 mm. 
In the atlas of Phascolonus the continuity of the anterior 
bony arch is interrupted by a vacuity as in Diprotodon, in the 
wombats and in some other marsupials, and the gap is of greater 
relative width (45 mm.) than in the forms specifically mentioned. 
In the atlas of a latifront wombat the interspace measures 10 mm. 
and in that of a Diprotodon only 26 mm. 
The neural arch is distinctly more flattened than in the 
wombat and the transverse process is grooved for the vertebral 
artery, but to a slight extent only. The neurapophysis is perfor- 
ated, for the passage of the first cervical nerve, in much the same 
way as in the wombat. 
AXIS. 
[A fragment comprising the body and odontoid process—the 
greater part of the neural arch being absent. | 
Such parts as are preserved, present, generally, the features 
found in the axis of Phascolomys but the odontoid process, 
which in P. latifrons is somewhat antero-posteriorly compressed, 
would appear to have been more conical in form though it is 
possible that the abrasion to which it has to some degree been 
subjected may have modified its original shape. 
Besides the bones that have been specifically mentioned above 
there exists also amongst the Callabonna remains about a dozen 
ribs, a few vertebral centra and two or three fragments of the 
pelvis. For the present we defer consideration of these. 
REMARKS. 
The preceding notes, which we hope may skortly be fol- 
lowed by a more complete, as well as adequately illustrated, 
description, will at least indicate the more conspicuous features 
of a large part of the skeleton of Phascolonus gigus. It has 
