128 
about half an inch below the tuberosity. From this point the 
width gradually declines until the shaft begins to broaden again 
into the distal expansion. In the wombat, on the other hand, 
the shaft is at its narrowest just below the tuberosity, thence 
gradually widening towards the lower end. In the fossil the 
bicipital tuberosity is proportionately smaller but more promi- 
nent and relatively more distant from the head than in the 
wombat. 
ULNA. 
{One specimen which lacks the lesser sigmoid cavity and 
(excepting its upper lip) that part of the greater cavity 
which is applied to the radial division of the distal humeral 
articulation. The styloid process, also, is not quite complete, but 
this is perfect in a second fragment comprising the lower half of 
the bone. | 
Length, 250 mm.; breadth (across thenal surface at level of 
inner division of humeral articular surface), 95 mm. 
Wombat :—Length, 135 mm.; breadth, 29 mm. 
To an immense olecranon process, which is proportionately 
larger than that of Phascolomys, is added, in Phascolonus, a 
marked production thenad of the proximo-thenal angle, the effect 
being to produce, in the region lying between the tip of the 
olecranon and the thenal side of the sigmoid cavity, a much more 
marked depression than exists in the corresponding part of the 
ulna of the wombat. The anconal surface both of the olecranon 
and shaft is traversed for nearly their whole length by a distinct, 
broad but shallow groove which, in the wombat, is scarcely 
apparent. The styloid process in the fossil is very distinctly 
semi-oviform with a marked inflection thenad ; in the wombat it 
is nearly circular in contour and obtusely conical in form. 
CARPUS. 
[Of the Carpus the cuneiform (one specimen), pisiform (two 
specimens), and unciform (two complete and three fragmentary 
specimens), only, are represented. | 
The first named combines phascolomydian and diprotodontoid 
features :* the pisiform almost exactly repeats on an enlarged 
scale the characters of this bone in the wombat, and is thus 
unlike that of Diprotodon ; the unciform, which possesses a large 
unciform process, is also chiefly phascolomydian in its characters. 
The carpal bones reveal an even greater proportionate size, 
when compared to those of the wombat, than do the long bones. 
* A description of the manus and pes of Diprotodon australis, forming 
part I. of vol. I. of the Memoirs of the Royal Society of South Australia, 
is now in the press. 
