* Seg 
624 REPTILIA. 
which are furnished with small pointed teeth. In the posterior region 
of the skull we have still to notice the large ex-occipitals with which the 
opisthotics are fused, and which are continued into the conspicuous 
parotic processes. The lateral walls of the brain-case are largely formed 
by the paired pro-otics. Internally, an important bone, the epipterygoid 
or “columella” (not to be confounded with the columella or stapes of 
the ear), extends from the pro-otic to the pterygoid. The orbit is 
Fic. 341.—Side view of skull of Zacerta.—After W. K. Parker. 
px., Premaxilla; x., maxilla; 2, lachrymal; 7., jugal; ¢.42., 
transpalatine ; efg., epipterygoid 3 Ag, pterygoid; dfg., basi- 
pterygoid; d.0., basioccipital; g., quadrate; oc.c., occipital 
condyle ; sg., squamosal ; v.0., pro-otic ; A¢.0., postorbital ; s¢.z, 
st.2, supratemporals ; Zs., presphenoid: (the optic nerve is seen 
issuing in front of the end of the reference line); Z.¢., mes- 
ethmoid ; s.oJ,, supraorbitals; 4%, prefrontal ;, 2., nasal ; a~., 
articular ; ag., angular ; sag., surangular; cv., coronary; @., 
dentary. 
bounded posteriorly and inferiorly by the jugals. There is no ossified 
quadrato-jugal, and thus the lateral temporal fossa is open below in the 
dried skull (contrast Ha¢terza). The other fossce of the dried skull are 
the supra-temporal on the upper surface, and the posterior-temporal on 
the posterior surface. 
Each half of the lower jaw is composed of six bones, which use in 
the adult. The two rami are sutured to one another in front. 
