300 Annals of the South African Museum. 



The humerus has lost the upper third, but the lower two-thirds, 

 including delto-pectoral ridge, is perfect. In general shape it 

 resembles considerably the humerus of Plateosaurus reinigeri, but is 

 only about half the size. The narrow part of the shaft is relatively 

 a little thicker in the present species, the lower end of the bone is 

 broader and the delto-pectoral ridge is narrower, and is more directly 

 continuous with the head of the bone. The following are some of 

 the principal measurements : 



Probable greatest length 220 mm. 



Breadth at distal end 77 , , 



Width at narrowest part of shaft 32-5 , , 



"Width at top of pectoral ridge 72 , , 



From lower end of pectoral ridge to furthest part 



of distal end 125 ,, 



The left ulna is almost perfect, only a small portion of the proximal 

 end being lost, and the left radius is even better preserved. This is 

 the more satisfactory in that in Massospondylus carinatus neither the 

 radius nor ulna is known, and in the other Triassic Dinosaurs the 

 bones of the forearm are rarely well preserved. In Pachysaurus 

 ajax both radius and ulna are known, but they are considerably 

 distorted. In Plateosaurus quenstedti they are better preserved. 

 In Massospondylus harriesi the radius is nearly straight, slightly 

 broadening at the upper and lower ends. The upper end has a 

 deep concavity for the condyle of the humerus. On the posterior 

 and inner side of the upper third is an oblique groove, probably for 

 the attachment of the biceps or huniero-antibrachialis. The lower 

 end of the bone is curved outwards a little, and the large articular 

 surface looks somewhat forwards. 



The ulna is in its upper half nearly twice as broad as the radius. 

 The lower end has the same peculiar twist already seen in Gryponyx, 

 but here it is more marked. The distal fourth of the bone is rotated 

 about 40 to the right. 



The following are the principal measurements of the bones : 



Greatest length of radius probably 128 mm. 



Width at proximal end 35 ,, 



Width at distal end 31 ,, 



Width in middle of shaft 19 ,, 



Greatest length of ulna probably 134 ,, 



Width at proximal end 57 ,, 



Width at distal end 41 ,, 



Width in narrowest part of shaft 25 



