222 
PROFESSOR H. G. SEELEY ON THE STRUCTURE, ORGANIZATION, 
above it, at the'back of the orbit, is pierced by a large foramen ; a similar foramen 
appears to be present at the back of the corresponding inter-orbital bone in the 
specimen termed Dicynoclon Murrayi (Huxley). This perforation I can only regard 
as the foramen for the olfactory nerve, and the bone as the orbito-sphenoid. A little 
further back, parallel to the cranial wall, but well separated from it, is a thin flat 
bone, which extends from the parietal region to the pterygoid; and I therefore 
identify it as the columella. There appears to be a distinct, suture towards the 
quadrate process between an outer and an inner element of the pterygoid, and a line 
which might be fracture or suture extends forward to tlie angle where the posterior 
end of the palatine is wedged into the bone. This furnishes some evidence, though 
no proof, that the long external bone may be the transverse bone. In other 
specimens it appears to be blended with the median element, for no suture has 
been detected on its palatal aspect. The following figure shows the relations of the 
median bones of the skull according to the interpretation now given. 
Fig. I. 
Obliqiiely crusted Dicynodont skull, wticli has lost its external arches and shows the hones between 
the orbit and squamosal region. The shaded parts are vacuities or spaces occupied with matrix. 
The fractures produced by the crushing make the recognition of the sutures difficult. The figure 
now given may be compared with Plate xxxiv., fig. I, ‘ South African Catalogue.’ 
i.p. Inter-parietal. 
col. Columella. 
f.s. Pre-sphenoid. 
orh.sp. Orbito-sphenoid. 
pt. Pterygoid. 
?tr. Apparently distinct from 
pterygoid, and, pos¬ 
sibly, the ti’ansverse 
bone. 
pal. Palatine. 
max. Maxillary. 
lac. Lachi’ymal. 
p.f. Pre-frontal. 
/. Frontal. 
pt.f. Post-frontal. 
