Annals of the Transvaal Museum 
79 
the bone is 9 mm. This ventral surface is deeply concave. The breadth of 
the hinder articulation surface is 14 mm.; that of the front end is smaller. 
Nothing is visible of diapophyses or parapophyses. The praezygapophyses 
are short, pointed and wide apart. The postzygapophyses are longer. The 
height of the front articulation surface- of the vertebra, where all these dimen- 
sions are taken from, is 10 mm. The third vertebra is very much shorter and 
is the only neck- vertebra showing a dorsal spine. The height of this vertebra, 
with its spine, measured in the middle of its length is 19 mm. The length of 
the spine ( i.e . from the anterior to the posterior end) is 18 mm. The height 
of the hinder articulation surface is 10 mm. This seems to be one of the fore- 
most vertebrae of the neck. 
Dorsal Vertebrae. 
The total number of dorsal vertebrae is 14. The vertebra which I take to 
be the first dorsal is largely covered by the coracoids. It is not impossible, 
although I think it very improbable, that there is another dorsal vertebra in 
front of this one. 
The first seven vertebrae are still articulating, but the eighth is displaced. 
The ninth to the fourteenth are also more or less in juxtaposition. They all 
lie on their left side and through the splitting of the stone all the vertebrae 
have been broken and greater or smaller portions of each are still in both 
slabs. Therefore, generally speaking, no detail of the outer surface of the 
vertebrae is visible. Their principal measurements are 
Dorsal vertebra No. 1 
Length of the centrum 
Height of front articulation surface 
Height of hinder articulation surface 
Total height 
Length of dorsal spine 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 13 14 
20 
21 
23 
24 
24 
24 
26 
28 
29 
15 
15 
16 
17 
15 
15 
15 
15 
17 
19 
36 
37 
37 
38 
39 
39 
37 
40 
16 
19 
22 
22 
22 
21 
From these figures and from the plates it will be seen that the vertebrae 
do not differ much in size. The length of the centra seems to increase slightly 
and gradually towards the pelvis. The dorsal spines are thin, long and low. 
Their front upper corner is rounded and their upper hinder corner more pointed 
and overhanging. Their upper border is evenly rounded, and its general direc- 
tion diverges slightly backwards with the axis of the centrum. The prae- 
zygapophyses project far beyond the plane of the anterior articulation surface 
of the centrum. The postzygapophyses are shorter, but still project well be- 
yond the plane of the posterior articulation surface. There is a round opening 
between the praezygapophysis and the anterior vertebra, which apparently 
served as an exit for a spinal nerve. The vertebrae are amphicoelous, but the 
only articulation surface visible is the rather deep depression on the hinder 
end of the first vertebra. The neural arch is attached to the centrum by a 
suture, which is plainly visible in the third to the sixth, the eighth to the 
tenth and the twelfth vertebra. This suture is seen on the outer surface of 
the vertebra as a zig-zag line, the general direction of which is parallel to the 
axis of the centrum. The amplitude of the undulations of this line seems to 
lie within certain limits, which are reached by many individual waves. The 
connection seems to have been a loose one and could only have prevented the 
neural arch from moving in a direction parallel to the axis of the centrum. 
Apparently centra and neural arches became easily disconnected, for this is 
more or less the case in five vertebrae. 
Ribs are present near all the vertebrae except the fourteenth and it is very 
probable that this vertebra did not bear ribs. The animal would then have 
6—2 
