158 
MR. W. K. PARKER OK THE STRUCTURE AUD 
inner face, growing into the sulcus between the swellings of the brain (C 3 ., C 1 .). Here 
the large optic foramen is a “ fenestra/ 7 as in Frogs; its upper margin is formed by 
this lower orbito-sphenoidal process (o.s.), and its lower edge by the trabecula (tr.); 
this plate now touches its fellow of the opposite side. The upper lip (u.l.) is seen in 
all its depth here, and the teeth (t.) are in full view ; they are looked at from behind. 
Section 8.—In this slice (Plate 14, fig. 14) the hinder half of the eye-ball and optic 
nerve ( e ., II.) is seen, and the brain (C 1 ., C 3 .) is here at its greatest bulk. The trabeculae 
(tr.) are confluent, are thicker, and rise more at the sides; this is close in front of the 
post-pituitary wall. The thick hind part of the orbito-sphenoid is now ready to 
become alisphenoidal; its two parts are molten together, and the upper tract or super¬ 
orbital ( s.ob .) is now thickening as it approaches the auditory sac, ready to become the 
postfrontal (“ sphenotic”) wing. 
Close behind the upper lip (u.l.) two curved plates of cartilage are cut across; 
these are the pterygo-quadrate bars (pg .q.), they are thick outside, and bevelled where 
they meet. 
Section 9.—In this section (Plate 15, fig. l) the mid-brain (C 3 .) is at its widest part 
and overlies the infundibular end of the fore-brain (inf.), to which the pituitary body 
(py>) is becoming attached; this is through the hinder part of the eye-balls (e), and 
close in front of the Gasserian ganglion (see fig. 2, Y.). 
The superorbital band is now the “ sphenotic ” (sp.o.) ; below it there is a large mem¬ 
branous fenestra, and the short oval section of the narrow alisphenoidal band (al.s.). 
The trabeculae (tr.) are apart again, where the pituitary body (py.) passes down; they 
are altogether narrower here, and are grooved by vessels below. Here the pterygo- 
quadrates (pg-qi) are cut through their middle part, and here, in the re-entering angle 
behind their upper junction, a considerable wedge of cartilage is seen ; this is the 
azygous metapterygoid (mt.pg'.) ; it has a pair of smaller pieces (mt.pg".) or lateral 
metapterygoids attached to it; underneath this arched palate a number of teeth 
(pterygoid teeth) are seen. 
Section 10.—This section (Plate 15, fig. 2) escapes both the eye-balls and ear-sacs, and 
is through the body of the Gasserian ganglion (Y.) and behind the pituitary body. 
Here the trabeculae are confluent again in front of the low post-pituitary wall and the 
end of the notochord. The sphenotic cartilage (sp.o.) is now ear-shaped in section, 
convex outside, and has two sub-concave inner faces, one applied to the skull-wall and 
one hanging down free. The pterygo-quadrates (pg-q-) are cut across a little in front 
of the hinge of the lower jaw, they are acuminate-oval in section, with the point down¬ 
wards. The lower lip with its teeth ( l.l., t.) is here displayed, and the large “adductor 
mandibulse ” (ad.m.) is cut across its belly. 
Section 11.—This (Plate 15, fig. 3) is the first of the auditory sections; the capsules 
(an.) are severed in their antero-superior-angle, to which is attached the upper and 
lower processes of the sphenotic (sp.o.). Through the wall of the capsules the 
ampulla of the anterior canal (a.s.c.) is seen. The alisphenoid (al.s.) re-appears in this 
