68 The Alligator and Its Allies 
surface of the basisphenoid is the pituitary fossa, 
not seen, of course, in this view of the skull. * 
The alisphenoids (crossed by the dotted line from 
V) are a pair of very irregular bones that form most 
of the antero-lateral walls of the brain case. They 
articulate dorsally with the parietal, frontal, and 
postfrontal; ventrally with the basisphenoid 
and pterygoid; and posteriorly with the quadrate 
and some of the otic bones not visible in this view. 
Between it and the quadrate, plainly visible in this 
view, is a large opening, the foramen ovale (V), 
through which, according to Reynolds, the tri- 
geminal nerve passes. In the middle line, directly 
under the frontal bone, is an opening between the 
anterior wings of the two alisphenoids, for the exit 
of the optic nerves. Ventrad and caudad to this 
opening, and sometimes continuous with it, is 
another large foramen, just dorsad to the rostrum, 
for the exit, according to Reynolds, of the oculo- 
motor and abducens nerves. Projecting caudad 
is seen the rounded condylar part of the bas- 
occipital (14) to be described later, and dorso- 
cephalad to this is a part of the exoccipital (13) 
in which four foramina may be seen; of the dorsal 
three the one nearest the condyle and foramen 
magnum is for the exit (Reynolds) of the hypo- 
glossal nerve (XII); slightly dorso-cephalad to 
this is one for the vagus nerve (X); between these 
two is a very small one for a vein; the largest and 
ventrally located foramen is for the entrance of the 
