DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
119 
liind part of the septum nasi ( s.n .), and the hiding ol the outer part of the bone by the 
vomers (see figs. 6 and 9). Contrary to rule, the upper and lower outlines of the nasal 
region are very similar. 
Above, a large and shallow, and, below, a narrow and deep, notch on each side, shows 
where the ethmoidal territory ends and the nasal begins, and these emarginations show 
that the nasal region is short; the thickness of the convex root hides the form of the 
dividing septum nasi. Below (figs. 6 and 9), the girdle-bone ends in a sinuously- 
Tounded margin, a short distance behind the notches in the sides. The bone is sinuous 
on its surface, first scooped in the middle, then swollen on each side, a groove sub- 
transversely dividing these swellings from the “wings.” In front of the notches, the 
subnasal laminae (fore part of trabecular cornua, s.n.l.) are ossified, each bone taking up 
one-third of the floor. A bone half the size of these has been formed in the cartilage 
of the median tract; it reaches from the nerve-passages ( n.n .) to the decurved rostrum 
(; p.n .). These three bones, like the ethmoid or “ girdle,” being ossifications of the 
three basi-cranial bars—like those found in so many types in the region of the brain 
cavity—may be entitled to the name of “serial homologues ” of such segment-forming 
bony centres.'" 
The lateral subnasal ossifications are rugged and prickly at their margins ; their 
middle is somewhat elevated, transversely; the “pro-rhinal process” of the cartila¬ 
ginous matrix ( p.rh.) is small. 
The upper surface, formed mainly (i.e., except at the middle line) by the nasal roof- 
cartilages (fig. 7, al.n.) is broad, gently convex, and passes insensibly into the prenasal 
rostum (figs. 5-7, p.n.). 
The suborbital space ( f.p. to pg.) is large and sub-oval; its outer fence is the palato- 
suspensorial arch. The ethmo-palatine bar, like the rest of the cartilaginous pith of 
this arch, is slender, and runs outwards and forwards, like a continuation of the wing 
of the ethmoid; it is bi-aculeate in front (fig. 9, e.pa.). The post-palatine portion 
(behind e.pa.) can be seen to be but little affected by the palatine bone (fig. 6), which 
is a normal sub-falcate blade, separated by almost its own length from its fellow, and 
not reaching the pre-palatine spur in front. But the pterygoid (pg.) either ossifies or 
conceals much of the hinder part, yet the inner fork or pedicle (fig. 5, pd.), and the 
tract leading to it in the edge of the folded pterygoid (fig. 7, pg., sp.) shows that the 
axis is nowhere quite lost. But on the under surface (fig. 6, pd.) the pedicle is seen 
to be tied down by the pterygoid bone so that all motion is lost, and this inner tongue 
of the bone forms a strong squamous suture with the prootic and parasphenoid ; this 
is a Bufonine character, as we shall see. 
But the outer fork, or quadrate region, becomes much larger, and the part above the 
condyle is largely ossified by the quadrato-jugal (figs. 6, 7, q., q.c., q.j.). 
* In Birds, ossifications of this kind in the precranial region of the base are very common; bnt in their 
compressed prognathous head the fore part of the intertrabecula is early absorbed ; the paired trabeeulce 
end behind the intertrabecula and the “ snbnasal laminae ” are only exceptionally developed. 
