PROFESSOR OWEN ON MACROPUS. 431 
produced. The coracoid (fig. 1, ¢) is represented by a meve tuberosity. The spine 
(ib. f) begins by an elevation (f") of the dorsal surface near the upper rounded angle 
of the base (4), and contracts as it rises to form a thin plate, slightly bent toward the 
infraspinal surface (j) ; and as it continues to rise, inclining to the supraspinal surface, it 
is continued at the neck of the scapula into an acromial process (¢) which extends 1 inch, 
4 lines from the fore part of the spine, and measures 3 lines across at its free end. 
This slender acromion is associated with a diminutive clavicle. 
There is a low tuberosity (a) below the glenoid cavity, but no trace of that singular 
production of the fore part of the inferior costa which distinguishes the scapula of 
Diprotodon’. A shallow depression extends along the almost even subscapular surface 
parallel with the origin of the spine from the opposite surface of the bladebone. 
The clavicle (P]. LX XVIII. fig. 3) is three inches in length, with a large reniform 
syndesmotic articular surface (fig. 4, a) at the sternal end, which is expanded accordingly ; 
the shaft contracts, becomes compressed, then slightly broadens at the acromial end, 
where a narrow ridge on the under surface of the hind border gives attachment to the 
short ligaments tying it to that part of the scapula. The non-articular surface (fig. 4, 4) 
of the sternal end is excavated. The bone is bent, with the convexity forward. 
The humerus (Pl. LX XVII.) of the Rufous, as of other Kangaroos, is slightly bent, 
with the concavity ulnad ; the tuberosities and ridges are strongly developed, and the 
entepicondyle is perforated. 
The articular head is large and subhemispheric (ib. fig. 4); it is produced anconad, 
so as to overhang that side of the shaft. The thenal third of the proximal end of the 
bone is occupied by the two tuberosities and their intervening (bicipital) groove. The 
ectotuberosity (ib. c) has the form of a long thick ridge; the entotuberosity (ib. 0) is 
shorter and thicker, strongly convex, and better bears the name of tuberosity; both 
rise above the level of the head (ib. fig. 2). The proximal end, showing the above three 
parts, is still in the state of an epiphysis. 
The proximal third of the shaft is four-sided; the two broader sides (ib. fig. 2, 7, 7) are 
on the anconal aspect, and meet at the round or obtuse ridge (ib. 2) continued from below 
the overhanging head one third down the bone. ‘The facet on the ulnar side (/) of the 
ridge is bounded at its lower half by the ridge (e) for the insertion of the “ pectoralis.” 
The two facets on the thenal side of the proximal part of the shaft are of unequal 
breadth; the broader one (ib. fig. 1, g) is flat, and is bounded below by the ridge ¢ 
and the stronger deltoid ridge (ib. d), which is continued below the middle of the shaft. 
The fourth facet (ib. f) is the narrowest; it is bounded on the outer (radial) side by the 
deltoid ridge, which is continued from the ectotuberosity downwards; a thicker ridge 
from the entotuberosity (ib. ¢) subsides upon a roughish surface (ib. fig. 3, v) about one 
third down the bone. The shaft contracts below the deltoid region, assumes the cylin- 
drical form for a short extent, and sends off the supinator ridge (ib. figs. 1 & 2, £’). 
1 Phil, Trans, vol. clx. p. 549, pl. slv. 
