168 EDWARD L. RICE 
6. ORBITOTEMPORAL REGION 
1. General description 
In his Lacerta paper (00) Gaupp applied the name ‘regio 
orbitalis’ to the entire section of the skull between the otic and 
ethmoid regions; later (05 b) he introduced the more adequate 
term ‘regio orbitotemporalis.’ The orbital and temporal sub- 
regions (figs. 1, 2, and 3), which together make up the orbito- 
temporal region, differ from one another as regards the extent 
of the enclosed brain cavity, the character of the cranial floor, 
and the character of the lateral walls; they resemble each other 
in the entire lack of a cartilaginous cranial roof. 
In dorsal view the brain cavity in the orbitotemporal region 
is strongly pear-shaped, with the stem end turned forward. In 
the narrow orbital portion are located the olfactory lobes of 
the brain; the enormously expanded temporal portion contains 
the cerebral hemispheres and optic lobes. It is hardly necessary 
to note that these statements can be only general; the morpho- 
logical divisions of the brain do not correspond exactly with the 
regional divisions of the skull. The contrast in the width of 
the orbital and temporal regions of the cranium is much more 
conspicuous in Eumeces than in Lacerta. In Gaupp’s figure 1 
the ratio of the maximum width of the temporal region to that 
of the orbital is barely more than two to one; in Eumeces the 
corresponding measurements give a ratio of at least three to one. 
In the temporal region the cranial floor is composed of the two 
trabeculae (fig. 2, trab.), the paired structure of which may be 
recognized even in their fused anterior parts; in the orbital region, 
on the other hand, the floor consists of the unpaired interorbital 
septum (figs. 2 and 3, sep.t-o.). The side walls of the temporal 
region are very rudimentary, consisting of a latticework of 
slender rods and bars of cartilage, while the walls of the orbital 
region are formed of the continuous plates of the solum supra- 
septale (figs. 1 and 38, sol.s-s.). The rudimentary character of 
the lateral wall of the temporal subregion is much more marked 
in Eumeces, at least in the later stages, than in Lacerta. 
