128 
Aotaus of the Teansvaal Museum. 
processes occur in Cacops and Trematops and according to Case (3, p. 132) 
they correspond with the hypapophyses of the reptilian basisphenoid. 
There is a groove on either side behind these processes. This groove 
bends upwards and forwards between the pterygoid and the corresponding 
condyle. 
No suture has been found between the basisphenoid and the para- 
sphenoid. The sutures between the basisphenoid and the pterygoids are 
clear. 
The greater part of the lower surface of the basisphenoid is covered 
with minute teeth (PI. XVIII.) Its hinder portion, however, is smooth 
and bare. The boundary between the smooth and teeth-covered surface 
has the shape of a hyperbole, with the apex near the middle of the lower 
surface of the bone. 
The parasphenoid is long and slender, connecting the prevomer with 
the basisphenoid. Broad in front, it gradually narrows down to where it 
joins the rhinencephalic chamber. Thence it broadens towards the basi- 
sphenoid. Its lower surface is smooth, except at the junction with the 
basisphenoid. Here a tongue-shaped surface, connected with the teeth- 
covered surface of the basisphenoid, is also covered with minute teeth. 
The pterygoid, from the articulation with the basisphenoid, sends out 
a transversely horizontal process, which soon bends forward to join the 
palatine. It also sends a horizontal process towards the quadrate. This 
process, from its point of origin, forms a thin, internally concave, upright 
plate, which is suturally connected with the edge of the bones forming 
the outer border and inner end of the otic notch. The upper front end of 
this plate is connected with the supratemporal. 
Of the palatal surface of the pterygoids only that of the process 
towards the palatines is known. This is largely covered with numerous 
small teeth. The pterygoids of skull No. 1 show a bare strip of palatal 
surface directly behind the palatines. Only a short portion of the bone 
along the palatines is known. This is also covered with small teeth. 
Further forward only the outer border of the right pterygoidal vacuity 
has been developed. This border shows small teeth right up to the 
prevomer. 
The palatines are long slender bones, which probably form the 
anterior borders of the infratemporal fossae. Their anterior ends are 
unknown. Near the middle of the lower surface there is a narrow, longi- 
tudinal ridge, which supports a series of large teeth. These teeth are 
clearly pleurodont, the ridge on which they stand projecting up to a third 
of their height along their outer side. The ridge starts near the hinder 
end of the palatine, but it is unknown how far it extends forward. The 
teeth on this ridge show the same dimensions as those on the maxillary 
and diminish in size backwards (figured in 2). On both sides of the ridge 
the palatine, for so far present, shows a smooth surface. 
Only a small strip of the hinder border of the prevomers is present. 
Near or at the junction of prevomer and palatine there are small teeth. 
This is the only part of the lower surface of the prevomer preserved. 
The occipital surface of the skull is badly preserved. In skull No. 1 
only the outline of the foramen magnum is visible, which is triangular. 
The height of this triangle is 20 mm., and the length of its base 25 mm. 
The right occipital condyle is well preserved in skull No. 2 (PL XXIV, 
fig. 3). The articular surface is slightly concave from above downwards 
