60 The Alligator and Its Allies 
tion, a thick process that unites with a similar 
process from the jugal to form the postorbital bar 
(pb) which lies between the orbit (0) and the tem- 
poral fossa (tf). The postfrontal forms the antero- 
lateral boundary of the supratemporal fossa. 
Articulating posteriorly and laterally with the 
parietal and the postfrontals, and forming the 
highest point of the skull, is the single frontal bone 
(24), which, like the parietal, is paired in the em- 
bryo. It is a heavy bone whose dorsal surface is 
flattened posteriorly, deeply concave in the middle 
region, and drawn out into a long projection anteri- 
orly. It forms part of the roof of the cranial 
cavity and articulates ventro-laterally with the 
alisphenoid and anteriorly with the prefrontals and 
nasals. It forms a part of the median boundary of 
the orbit. 
The prefrontal (4) is an elongated bone in the 
latero-median border of the orbit. Medially and 
anteriorly it articulates with the frontal and nasal, 
laterally with the maxillary and lachrymal, and 
ventrally, by a heavy process, with the pterygoid. 
The nasal (25) is a long narrow bone forming the 
greater part of the roof of the nasal passage. 
Along the median line of the skull it articulates 
with its fellow; posteriorly with the frontal; 
laterally with the prefrontal and maxillary; and 
anteriorly with the premaxilla. In the crocodile, 
caiman, and gavial it also articulates with the 
lachrymal. In the alligator the anterior ends of the 
