MESOSATJEIA OP SOUTH AFRICA. 589 



former being apparently about 5 millimetres, and of the latter about 

 11 mm. The prezygapophyses extend in advance of the face of the 

 centrum, but are rather short, and look upward and inward. The sides 

 of the neural arch are inclined obliquely outward, are convex from 

 above downward, and look outward and upward. The transverse 

 processes or caudal ribs are strong, subcorneal, almost horizontal 

 processes, 9 millimetres long, compressed from above downward into 

 a wedge-shape at the outer extremity ; while they are flattened ver- 

 tically in front at the base, which is 4 millimetres deep, where the 

 process is given off from the conjoined centrum and neural arch. 

 The processes are directed outward and a little downward. The 

 neural spine is short, and in front it is sharp ; the height from the 

 base of the centrum to its summit is 1*5 centimetre. 



The posterior aspect shows similar characters in the neural arch, 

 except that the lateral convexity is rather greater, and the height is 

 rather less. The posterior zygapophyses are compressed from above 

 downward, and look obliquely downward and outward ; the trans- 

 verse width over them is about 7 millimetres, being apparentlj^ 

 rather less than the anterior measurement. The neurapophyses do 

 not extend to the hinder face of the centrum, but are notched out 

 in the usual way to form the intervertebral foramen. The centrum 

 is convex on the under side, as in the dorsal region, but its dimen- 

 sions contract markedly towards the concave posterior articulation. 

 The transverse process or caudal rib appears to be flattened on its 

 under side ; it is about 1*2 centimetre long. 



No. 3. — 49974. Presented by Captain Scott Helps ; from the 

 cutting at the east of Kimberley Mine, facing Claim '018, 40 feet 

 from the margin and 50 feet deep ; January 1878. This specimen 

 shows an impression of a few early caudal vertebrae, very imper- 

 fectly preserved ; and an impression of the hind foot with the distal 

 row of the tarsus, the metatarsus, and digits having the formula 

 2-3-4-5-4. 



The inflated sides of the neural arches are shown in five vertebrae, 

 and the stout, subconical, transverse caudal ribs attached to them 

 diminish from a length of 1'5 centimetre in the earliest to about 

 4 millimetres. These processes are rounded ; their shortening in 

 these five vertebrae may be taken to indicate that they are speedily 

 lost, and that the sides of the caudal vertebrae then become flattened. 



The evidence concerning the hind limb, though fragmentary, is 

 instructive. The distal row of the tarsus is preserved and consists 

 of five subovate cuneiform bones, of which the fifth is very small.^ 

 One of these bones articulates with the proximal end of each meta- 

 tarsal (as in Cryptohranchus and Salamandra). On the external 

 side of the slab, above the small fifth cuneiform bone, is the large 

 broadly wedge-shaped cuboid, and above the other bones a part 

 only is preserved of a larger bone which the evidence does not 

 enable me to identify. 



The metatarsal bones progressively increase in length, and there 



1 This fifth bone is much smaller than in Stereosternum. 



2s2 



