190 Annals of the South African Museum. 



been a very thick pad of cartilage ; in fact, the whole articular region 

 must have been cartilaginous. Both in front and behind the distal 

 portion is moderately fiat, but there is a distinct rounding of the 

 posterior part of the outer condyle. A shallow groove runs down 

 the back of the bone between the two condyles, and on the outer 

 margin of the condyle there is a well-marked narrow groove. The 

 width of the distal end of the humerus is 190 mm. The thickness 

 of the outer condyle is 78 mm., and of the inner 70 mm. 



The humerus of Belodon is very diiferent in its proportions to that 

 of Erythrosuchus, the former being slender with ossified articular 

 ends, the latter massive with cartilaginous ends. Apart, however, 

 from this the two bones are in structure essentially similar. The 

 delto-pectoral ridge is very small in Belodon, but bears the same 

 relation to the end of the bone as does that of the South African 

 genus. The distal end of Belodon is small, but also has a groove 

 on the outer side of the external condyle. The humerus of 

 Stagonolepis is not well known. Huxley figures three humeri, but 

 the figures are indifferently executed, and the descriptions not very 

 satisfactory. From his Fig. 6, Plate X., it is clear that there is a 

 large deltoid ridge as in Enjthfosuchus, and there is evidently also a 

 groove on the outer side of the external condyle. It would thus 

 appear that the humerus of Erythrosuchus resembles more closely 

 that of Stcujonolepis than that of Belodon, but even here the resem- 

 blance is not very close, as the humerus of Stagonoleins is slender. 



Radius and Ulna. 



The right radius and ulna were fortunately found side by side, so 

 that there can be little doubt as to which is the proximal end of the 

 bones. 



The radius is moderately straight, with a fairly uniformly thick 

 shaft, and considerably expanded at both ends. The proximal end 

 is narrower than the distal but much broader. When viewed from 

 above it presents an elongated elliptical shape, being 107 mm. in 

 breadth and 58 in thickness. It is fairly flat but excavated in the 

 centre, and with the outer and posterior corner prominently 

 developed. It was doubtless covered by a thick pad of cartilage. 

 About 50 mm. below the top of the bone there is on the anterior side 

 a well-developed muscular impression, probably for the biceps. The 

 distal end is moderately rounded, being 86 mm. by 73 mm. The 

 surface is flat, but very rough for the attachment of the pad of car- 

 tilage. The shaft slopes regularly outwards to the distal end except 



