DEVELOPMENT OF THE SKULL IN THE LACERTILIA. 
C07 
From the pituitary fossa to the end of the snout, the coalesced trabeculae are 
marked as the thick, rounded, lower edge of the orbito-nasal septum. 
In front of the ethmo-presphenoidal fenestra (c.f.f), this wall is thickened, rises 
higher, and then gradually lowers forwards ; at its highest part it is fused with the 
nasal roof (fig. 7). 
The sudden rise of the septum is due to the fact that there is an olfactory recess, as 
in “Mammals,” where the first pair of nerves are given off to the nasal mucous 
membrane (fig. 7,1) ; there is, however, no crifriform plate, but merely a single aperture 
on each side of the septum. 
A little further out, under the floor of this recess, the orbito-nasal nerves (V 1 ) are 
seen to pass on their way to the front of the snout. 
The winged top of the septum—the wings are the nasal roofs—ends in front of the 
basal part, which retires a little, and is emarginate in the front (Plate 43, figs 1, 2, s.n .); 
the thickening above is where the roofs have been cut away ; the notch below is caused 
by the bend of the trabeculae. 
The vomer, septo-maxillary, and nasal glands (fig. 1 ,v.,s.mx., n.g), here rise upon the 
side of the septum; the upper bone is the one mistaken for the inferior turbinal : a 
true cartilaginous rudiment of which I shall soon describe. 
I may now, before passing on to the transversely vertical sections, recapitulate the 
open spaces to be seen in this curious cranial basket. 
Above (Plate 43, fig. 7), there is the great fontanelle (fo.), ending in the rounded 
notch on each side of the rostral cartilage of the superoccipital (s.o ). This space is 
imperfect in front, and for the most part is hourglass-shaped, being pinched in by the 
“ epi-pterygoids.” Where this fontanelle ends in front, over the olfactory recess, there 
are the olfactory foramina; under this part, those for the orbito-nasals (V 1 ) ; the right 
and left fenestra) in the nasal roof (olf ) ; and the external nostrils ( e.n .), laterally. 
Most of the passages and spaces can be seen inside a half-skull (Plate 43, fig. 2), but 
only on the outside can be seen the auditory fenestrte (fig. 8, fo.,fr .); and the nerve 
passages, behind, not so clearly. 
But in the section (fig. 2) there are, on each side of the foramen magnum, or great 
doorway, the posterior and anterior condyloid foramina, the double hole for the 9th and 
10th nerves, the double “Meatus” for the 7th and 8th, the large “foramen ovale” (V), 
the great lower fenestra between this and the alisphenoidal stem, and a hole at the 
base of that stem. Above, from the prootic forwards, two great fenestrse and one 
great notch; below, the common optic fenestra (II), the orbital notch ( i.o.n .), and the 
cranio-facial fenestra {c.f.f.). 
The large, bulbous, fenestrate nasal labyrinth (Plate 43, fig. 7), with the pedate 
antorbital rudiments of the etlimo-palatine bars ( e.pa .), will be only understood by 
* I scarcely need refer to my recent description of tlie skull of the Snake—a tard solid case, the 
extreme contrast of this little Lizard’s Skull, but made of tlie same clay, and the same bricks and tiles. 
MDCCCLXXIX. 4 I 
