PEOFESSOE OWEN ON MACROPUS. 



441 



The inner production has more vertical extent, and is impressed by a longitudinal 

 channel: it supports the surface (fig. 6, I) for that so marked on the navicular part of 

 the astragalus (fig. 4). The ridges, so formed (figs. 1 & 2, m, n'), afford fulcral resistance 

 to the strong tendons gliding along the concave channels (ib. b, b') from the leg to the 

 foot beneath them. A well-marked groove (fig. 7, o) divides the fore part of the 

 "sole" of the calcaneum from the apical part of the cuboidal articular facet (e,f). 



The navicular (fig. 1, n) is a small, oblong, subquadrate, compressed bone, pre- 

 senting a narrow concavity to the facet (/) of the astragalus (figs. 4, 5), and an oblong 

 undulate surface divided between the proximal ones of the ento- (c i) and the ecto- 

 (c e) cuneiform bones. 



The ectocuneiform (ib. fig. 9) expands posteriorly into a distally bent tuberosity (fig. 9, t). 

 The outer side of the articular part of the bone is applied to the cuboides (figs. l&2,cb) 

 and to part of the proximal surface of the fourth or great metatarsal (ib. iv) ; the distal 

 articular border supports the proximal ends of the ento- (c i) and meso- {cm) cuneiform 

 bones. The small compressed mesocuneiform has coalesced with the proximal end of 

 the metatarsal, ii, in the skeleton of Macropus rufus here described. 



InM. major the inner slender metatarsal (cut, fig. 1, ii) 

 answering to the second in the pentadactyle foot, aiti- 

 culates at its proximal end with both the ento- (c i) and 

 the meso- {cm) cuneiform bones. 



The entocuneiform {ci) is an oblong flattened bone 

 10^ lines long, 4 J lines broad, notched at its hind margin. 

 It is pushed inward and backward, articulates by its 

 upper (proximal) end or surface with the scaphoid, by 

 the inner surface of its proximal part with the ecto- 

 cuneiform {ce) which it overlaps, by its anterior border 

 and contiguous inner surface of its distal half with the 

 mesocuneiform {cm), and by its distal end with the major 

 part of the proximal articular end of the metatarsal (ii). 

 From the lower part of the posterior notch a ligament 

 or tendon extends along the back part of the articulation 

 between m iv and the cuboid. 



The mesocuneiform {cm) is also a compressed ossicle, 

 of smaller size, wedged between the entocuneiform, the 

 proximal ends of the two small metatarsals {m ii, m iii) 

 and the ectocuneiform {ce). The back part of the proxi- 

 mal ends of m iii for an extent of five lines, is ligamen- 

 tously and closely connected with the mesocuneiform; 

 but the proximal articular surface of m in joins the fore 



_i.rii j'1.1 r p i-\ , • t> f \ Parts of tarsus and metatarsus, 



part 01 tne distal surface oi the ectocuneiform {ce). Macropus major. 



VOL. IX. — PAKT viii. Iforc/i, 1876. 3o 



