Annals of the Transvaal Museum 117 
ments of the head: length of the medial side n cm., of the lateral side 9-5 cm. 
and greatest breadth 7-5 cm. ( 4 , p. 42). These dimensions in our form are 
13 cm., 9 cm. and 8*5 cm. respectively. From these measurements it will be 
clear that the relations of the two bones are different. In Massospondylus 
carinatus the distal end of the tibia has the following dimensions: length 
anterior border 6 cm., medial border 4-5 cm., posterior border less than 4 cm. 
and lateral border 4 cm. In our form these dimensions are respectively 8*2 cm. , 
5-6 cm., 6 cm. and 4*2 cm. In Massospondylus carinatus the medial border of 
the distal end is longer than the posterior border, in our form it is the reverse. 
The above-mentioned differences may be regarded as sufficient to exclude our 
form from the genus Massospondylus. 
Massospondylus Harriesi is very much smaller than our form. The distal 
end of its femur, measured from the lower end of the trochanter quartus, is 
15*5 cm. In our form this portion measures 28 cm. The proximal end of the 
tibia of Massospondylus Harriesi measures 10-2 cm. x 5-2 cm. If the same 
relations existed in our form as in Massospondylus Harriesi the tibial head 
of the last should have a length of 13 x 15-5 : 28 = 7-2 cm. The head of the 
tibia of Massospondylus Harriesi is therefore much longer than in our form. 
Length and breadth of the head of the tibia in our form are 13 cm. and 
8-5 cm. respectively. If the same relations existed, the breadth of the head 
of the tibia in Massospondylus Harriesi, with regard to its length, should be 
8-5 x 10-2 : 13 = 6-67 cm. Therefore, the head of the tibia in Massospondylus 
Harriesi is relatively narrower than in our form. 
A comparison with Aetonyx palustris is difficult, because what is present 
in the one is missing in the other ( 7 , p. 304). In Aetonyx palustris the width 
of the lower end of the humerus is 5-7 cm. In our form it is 9 cm. The length 
of the humerus in Aetonyx is 17-4 cm. If the same relations exist in our form, 
the length of our humerus should be 17-4x9: 5-7 = 27-5 cm. In Aetonyx 
palustris the lower end of the delto-pectoral ridge lies 10 -i cm. from the upper 
end of the bone. This measurement and the length of the bone have been 
verified in the figure and were found to be correct. The distance of the lower 
end of the delto-pectoral ridge from the distal end of the bone, measured in 
the figure, is 9-2 cm. This may be slightly more in reality through fore- 
shortening, and also because of the damaged condyle. With the same rela- 
tions the lower end of the delto-pectoral ridge in our form -should lie at a 
distance of 9 x 9-2 : 5-7 =^i4-4 cm. from the distal end. With regard to the 
curvature at the upper end of our fragment and after comparison with other 
humeri, I come to the conclusion that it must lie at a distance of, at the very 
most, 13 cm. from the distal end. However, with a slightly longer upper end 
the total length of the bone would then come near the result obtained above. 
In Aetonyx palustris the proximal width of the second metatarsale is 2-5 cm. 
and that of the third metatarsale 2-6 cm. It could not be made out whether 
Dr Broom means the greatest dimension of the proximal ends or the breadth 
along one of the borders of the bones. From the description of Massospondylus 
Harriesi, however, I conclude that the greatest dimension is meant. In our 
form the greatest dimension of these two ends is 6-7 cm. and 5-6 cm. respect- 
ively. The greatest breadth of our metatarsale II is 4-1 cm. and of metatar- 
sale III 3-6 cm. In both cases, therefore, the proximal end of our metatar- 
sale II is larger than that of metatarsale III, whereas in Aetonyx palustris 
the proximal end of metatarsale III is only slightly wider than that of meta- 
tarsale II. 
The head of the tibia is relatively shorter in Thecodontosaurus skirtopodus 
than in our form ( 4 , p. 44). The femora of Thecodontosaurus Browni (2, p. 124 
