172 EDWARD L. RICE 
stage 6 the cartilage is almost perforated at this point. In 
stage 4 the principal fenestra is present, but the other fenestrae 
(or thin spots) of stages 5 and 6 are unrecognizable. Finally, 
in stage 2, there is no fenestration; the septum, interorbital 
and nasal, extends as an uninterrupted plate from the cartilago 
hypochiasmatica to the tip of the nose. Thus the septum is 
already in regressive development in the later stages of Eumeces. 
It is a very natural suggestion that this degeneration and fenes- 
tration of the septum interorbitale are but a later step in its 
development—that the very forces which have displaced the 
brain upward and led to the formation of the septum have by 
their continued activity also caused the resorption of parts of 
the earlier continuous cartilage. As chief among these forces 
we may well follow Gaupp in emphasizing the pressure exerted 
by the enormously developing eyes. In Sphenodon Schauins- 
land (’00) and Howes and Swinnerton (’01) describe a similar 
transition from an early imperforate to a later fenestrated con- 
dition of the septum. Other data are isolated and have no 
bearing on the present point. In Chelydra Nick describes three 
fenestrae, in Chelone and Dermochelys none. Kunkel (12 b) 
also describes an imperforate septum in Emys, and Shiino (714) 
in Crocodilus. 
The solum supraseptale belongs alike to the floor and the 
lateral wall of the cranium in the orbital region. Its considera- 
tion is more convenient in the latter connection (p. 181). 
3. Basipterygoid process and associated structures 
At the posterior limit of the temporal region is located a group 
of structures closely associated with one another and with the 
pterygoid bone, which may well be described together at this 
point, although of diverse origin and relations—the processus 
basipterygoideus, cartilago articularis ossis pterygoidei or men- 
iscus pterygoideus, processus pterygoideus quadrati, and epi- 
pterygoid. In adopting Parker’s (’79 and earlier) term ‘epi- 
pterygoid’ for the latter structure, in preference to ‘antiptery- 
goid’ (suggested by Gaupp, 791 a, and still used in ’00), I follow 
