76 
Annals of the Transvaal Museum. 
angle is 180 degrees (PL XI). In the middle they are only very slightly 
convex towards the face, while they bend broadly with the concavity 
forwards, towards the orbital cavity. This same bend occurs in latirostris, 
but there it is very small. 
The outer surface is rough and convex. There are deep pits near 
the frontal edges of the bones, while the broad thick ridges, which divide 
the upper suface of the skull from the preorbital part, are situated nearer 
to the middle. The orbital surface has not been developed, because there 
were chances of breaking the fossil. The outer edge of the bone projects 
far over the orbital cavity. 
Dimensions : 
Greatest breadth 58 mm. 
Greatest distance between the orbital edges of the bones 138 mm. 
Greatest distance between the points where the sutures 
with the frontals pass over the orbital edges 93 mm. 
As already mentioned on a former occasion, the latter distance in 
latirostris is 81 mm., and we therefore see that latirostris is only slightly 
narrower in this region. 
The Frontals. 
The whole upper surface of the skull is concave, except that part 
which is formed by the prefrontals behind the prefrontal ridges (PI. XI). 
The edges of the frontals rise up high against the prefrontals and 
towards the borders of the orbital cavities. All along the mutual suture 
they show a broad but low thickening. 
Dimensions : 
Length of the mutual suture on the upper surface 37 mm. 
Distance between the upper and hinder corners of the 
orbital cavities 95 mm. 
If these and some of the dimensions given under the prefrontals are 
compared with those of latirostris , it will be seen that the orbital edges 
of the frontals in latirostris converge strongly backwards, while those of 
Putterilli converge forwards. At the most these may be taken to be 
parallel. 
The lateral surfaces of the bones along the upper part of the orbital 
cavity, which have been found so perfect in latirostris (4, p. 17, 19, 21), 
are also present in this form. Those of the prefrontals stand vertical, 
but the lateral surfaces of the frontals incline towards the orbital edge, 
making a small angle with the orbital surface. The greatest breadth of 
the prefrontal ones is 17 mm. and of those of the frontals 18 mm. 
Compared with Mccaigi it will be seen that Putterilli is 20 mm. broader 
between the upper and hinder corners of the orbital cavities. 
The Postfrontals. 
The sutures with the adjoining bones cannot be made out, and there- 
fore all that can be said of the postfrontals is that they must be very 
broad at the edge of the orbital cavity. 
