CHONDROCRANIUM OF EUMECES 187 
these fenestrae retain approximately the same absolute size, 
but are relatively smaller than in stage 5. At the anterior and 
posterior the tectum runs in as a point between the fenestrae 
of the two sides, but in the middle the two fenestrae are sepa- 
rated only by the free upper edge of the septum. Functionally, 
the lack of cartilage in this region is compensated by the strong 
early development of the nasal bones (figs. 1 and 28, os na.), 
which, even in stage 5, form an almost complete roof over the 
fenestrae. The fenestrae superiores are present in Lacerta, 
although decidedly smaller than in Eumeces, and in Sphenodon, 
according to Schauinsland (00) and Howes and Swinnerton 
(01). Ogushi (11) figures very large fenestrae in adult Trionyx, 
but I find no other record of their presence in turtles, crocodiles, 
or snakes. Their absence in Emys is positively affirmed by 
Kunkel (12 b), nor do they appear in the figures of Nick (’12) 
for Dermochelys, Chelone, and Chelydra, of Parker (’83, repro- 
duced by Gaupp, ’05b) for Crocodilus, or of Peyer (’12) for 
Vipera. 
In the posterior third of the ethmoid region the tectum is 
extended uninterruptedly into a pair of great, ear-like, lateral 
expansions which roof over the extraconchal recesses of the 
nasal capsule (figs. 1 and 26, p.ext.); at the extreme front, also, 
it forms a projecting lobe on each side, extending a little in 
advance of the nasal septum (fig. 1). Laterally the tectum goes 
over, without interruption and without sharp demarcation of 
any kind, into the lateral wall or paries nasi. 
Two pairs of small foramina penetrate the tectum nasi. The 
one pair, foramina apicalia (fig. 1, f.ap.), are located at the sides 
of the extreme anterior end of the septum; the others, foramina 
epiphanialia (figs. 1 and 26, f.ep.), are located in the neighbor- 
hood of the conchal infolding of the nasal wall. These foramina 
serve, respectively, as exits for the two main branches of the 
ethmoid ramus of the trigeminus nerve. 
