RECORDS OF W.A. MUSEUM. 
[25 
head of the radius, which is concave, is irregular in outline, being 
much less circular than the same portion of the skeleton of 
P. latifrons ; the “ narrow semi-elliptical convex surface,” which is 
on the posterior edge of the head, and fits into the “ radial 
concavity of the ulna,” is not quite as deep as is shown in the 
figures referred to. On the other hand, the distance between this 
feature and the “ tuberosity for the biceps ” agrees exactly, though 
our bone is somewhat longer from end to end. This tuberosity is 
not by any means as prominent as in P. latifrons. Proceeding down 
the shaft it will be noticed to increase gradually in thickness, and 
also that it tends to assume a triangular shape — one of the angular 
ridges being that for the insertional fascia of the “ supinator longus ” 
—and gaining in sharpness till it reaches a small tuberosity at the 
distal end, just above the base of the short, thick styloid process.. 
It is also possible to trace the rough tract on the interosseal 
ridge or angle, situated in relatively the same position as on the 
bone of the figured species. 
Prof. Owen states that this bone is less thick in proportion to 
its length in P. platyrhinus (P. mitchelli ) than in the latifront species, 
but in the new form it is considerably so, as may be seen from the 
appended measurements, besides, though Owen states that the 
radius is “ slightly bent with the convexity forward ” his figures, 
however, show a bone which is much less arched than this 
specimen, for it is impossible to place this bone in a position which, 
whilst giving a straight outline, shows up the features as illustrated 
in Owen’s figures. 
TABLE OF MEASUREMENTS. 
Measured 
Measurement 
Features. 
on Owen’s 
OF CAVE 
figure. 
SPECIMEN. 
Total length 
107mm. 
111mm. 
Width at head (proximal end) 
i4^-i5mm. 
I2jmm. 
Width below the tuberosity for the biceps . . 
10mm. 
9 mm. 
Width at rough tract on interosseal angle . . 
13mm. 
12 mm. 
Width at tuberosity at distal end of bone 
23-24111111. 
22jmm. 
The Ulna. Both the right and the left are in very good condi- 
tion and therefore a satisfactory examination can be made. Owen 
states (loc. cit.) that the platyrhine and the latifront species resemble 
one another to a very great extent as far as this bone is concerned. 
He notices that “ the ulna of P. latifrons differs chiefly from that of 
P. platyrhinus in the quadrate form of the long olecranon which 
