385 



ridges of the centrum in the fifth caudal. In this vertebra the praediapophyses (ib. 

 fig. 12, pd), are developed; they are thence continued along a great part of the caudal 

 region. The haemal arch is strengthened ; its spine shortened, but extended lengthwise 

 (fig. 13, h s). A pair of hypapophysial ridges, beginning in the third caudal, form the 

 sides of a canal at the fore part of the fifth and following caudals (fig. 12, hi/). 



The haemapophyses articulate with the tubercular expansions of the hypapophyses by 

 almost flat subcircular surfaces (figs. 14-16, h, h), which coalesce in the fifth and 

 succeeding vertebra?, circumscribing the haemal arch or canal exclusively of the centrum. 

 These haemal arches develop ectapophyses (ib. figs. 15, 16, e, e), which are vertical 

 homotypes of the diapophyses of the neural arch. The fore-and-aft extension of the 

 haemal spine is greatest in the seventh caudal (fig. 13, h s, h s'). Beyond this the haemal 

 spines gradually decrease (ib. figs. 15 & 16), and the arch is finally reduced to simple 

 lozenge-shaped plates overlying the joint between two caudals. I find the last of 

 these at the antepenultimate of such caudal joints in Macropus rufus. 



§ 4. Bones of the Fore Limbs. — The scapula (PI. LXX. fig. 1) is broad in proportion 

 to its length ; the supraspinal plate (i) extends so as to describe a bold convexity (g') 

 along the major part of the upper border or "costa;" and the infraspinal plate (j) 

 expands to the rounded postinferior angle of the bone (h) ; both tracts are almost flat, 

 and the supra- and infraspinal fossae are comparatively shallow. The glenoid cavity 

 (ib. fig. 2, d) has the usual ovate form, with the small end next the coracoid (c). The 

 outer border, or that next the acromion (e), is sharp and rather produced. The coracoid 

 (fig. l,c) is represented by a mere tuberosity. The spine (ib. f) begins by an elevation 

 (f) of the dorsal surface near the upper rounded angle of the base (#), and contracts 

 as it rises to form a thin plate, slightly bent toward the infraspinal surface (j) ; then, 

 inclining to the supraspinal surface, it is continued at the neck of the scapula into an 

 acromial process (e). 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 (PI. XXX. a). 



The clavicle (PI. LXX. fig. 3) has a 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, b) of the sternal end is excavated. The bone 

 is bent, with the convexity forward. 



The humerus (PI. LXIX.) of the Rufous, as of other Kangaroos, is slightly bent, 

 with the concavity ulnad ; the tuberosities and ridges are strongly developed, and the 

 entepicondyle (i) 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 



