246 Prof. Owen on the Reptilian Fossils of South Africa. 



Scapular Arch. — The bone represented in fig. 2, s, g, & tig, 3, PI. XXXIV., is 

 either a scapula, or a ' coracoid.' Its glenoid or articular process (g) is subtriangular, 

 5^ inches by 4^ inches in the long and short diameters, divided at its extremity 

 into a symphysial surface for articulation with the scapula, and into the portion of 

 the glenoid articular cavity. The bone, as it extends from this twofold articular 

 end, contracts, and chiefly in transverse diameter, to a subcompressed neck, 

 thickest and rounded behind, 3 inches 9 lines in fore-and-aft diameter, 2 inches 

 in thickness, 5 inches in vertical extent at the back part, and 2 inches in the same 

 dimensions at the fore part. The bone above this constriction suddenly expands 

 into a broad semioval strong plate ; 12 inches in antero-posterior extent, 6 inches 

 in vertical diameter, and about 2 inches thick at its thickest part (s). This plate 

 extends about 2^ inches in advance of the neck, and terminates anteriorly in a 

 convex border ( x ) ; from this part it increases in vertical extent to the middle of 

 the bone, and continues slightly diminishing to the hinder border (x x), which is 

 nearly vertical : the upper border is moderately convex, and the angle is rounded 

 off by which it passes into the hinder border. The whole outer surface of the 

 expanded plate of the bone is slightly concave. 



The inner surface, fig. 3, is moderately convex, and a great proportion of it, 

 including the whole fore-and-aft extent and 5 inches vertically, is occupied by 

 a rough irregular, apparently synchondrosal surface. This structure, with the 

 modifications of the ilium and sacral ribs before described, indicates the power of 

 the Dicynodon to support and move itself upon dry land, like the Crocodiles, and 

 to a degree probably equalling that of the Dinosaurs. 



Supposing the above-described bone to be a ' scapula,' there is, then, a third 

 bone, c,p, fig. 2, perforated like the ischio-pubic bone, but difl^ering in shape. 

 It may be a coracoid bone : it bears a certain resemblance to the coracoid of 

 the Iguanodon. 



Humerus or Femur. — Of the long bones of the extremities, the most intel- 

 ligible is one which is remarkable for the slenderness of the shaft in comparison 

 with the extreme expansion of its distal end ; PI XXXI V. fig. 4. The shaft is 

 trihedral, with the angles rounded off, 3 inches in its longest diameter about an 

 inch above the beginning of the expansion of the distal end. The fractured 

 surface, here, shows no trace of a medullary cavity. From one side of this part 

 of the shaft a strong ridge is continued outwards and downwards, which expands 

 as it descends ; it resembles the supinator ridge of the humerus in carnivorous 

 Mammalia. The condyle which swells out anterior to this ridge is convex 

 and of large size. The outer part of the other and smaller condyle has been 

 broken away ; the under part of the condyles is gently concave from side to 

 side : the back part of the expanded end is very slightly concave, so far as it is 



