1911] Bryant: Horned Lizards of California and Nevada 9 
developed horns. The pineal foramen is usually at the coronal 
suture but may pierce the parietal alone. The paraoccipital is 
small and partially hidden by the occipital. The supraoccipital 
forms the superior part of the foramen magnum and articulates 
anteriorly with the parietal. The occipital condyle is formed 
by ossified processes from the basioccipital and lateral occipital 
elements. The sutures of the occipital elements are lacking. 
The postorbitals are slender but articulate broadly with the 
frontals and parietals above and the supratemporals and jugals 
below. The supratemporals and jugals are projecting and bear 
spiny tuberosities except in P. douglassi and P. cornutwm, where 
they are lacking or reduced to mere tubercles on the jugals. The 
quadrates are at an angle to the vertical and present an external 
conch only, the inner surface being convex, whereas in all other 
iguanids except Hublepharis and Celestus, it is concave (Cope, 
1898). The short vomers are separated by a narrow hiatus 
which broadens between the wide, toothless palatines and the 
pterygoids. The palatines possess processes which run forward 
and outward and join the vomers in front. The palatine fora- 
mina are small and vary in shape. The short, wide pterygoids 
run forward from the quadrates to the basi-pterygoid processes 
of the sphenoid, then broaden out and articulate with the pala- 
tines. These elements are edentulate. The ectopterygoids are 
irregular in shape and articulate with the palatines for only a 
short distance. The petrosals are short and grooved inferiorly. 
The slender epipterygoids are peculiar in that they reach only 
to the petrosals. They originate just behind the ectopterygoid 
processes. 
The Meckelian grooves may be open or partly closed by ecar- 
tilage. The coronojds are situated just above the sutures between 
the angulars and the dentaries and articulate broadly on the 
interior surface of these two bones. The pleurodont teeth, one 
row on each dentary, are small and bluntly conical. The 
articulars are sometimes ossified with the surangulars. 
The basihyal is wide and ossified. The rod-like anterior 
cornua are also ossified. The middle cornua are usually ear- 
tilaginous, very broad at the tip, and attached to the anterior 
