158 
ME. W. K. PAEKEE OX THE STEITCTITEE AND 
We now see Meckel’s cartilages {ink.) and the lower labials ( l.l .) from behind; the 
quadrate, however, is shown in section. Here we get a perfect idea of the relation of 
the first two visceral arches, for the section has been made through the secondary band 
or pterygo-palatine bar (pa., pg.). 
The remarkable “orbitar” process is shown embracing the temporal muscle ( or.p ., t.m.) ; 
and this muscle is almost entirely surrounded by cartilage ; for there is a “ pterygo-pala- 
tine process ” (well seen from above in Plate V. fig. 3, p.p.p.), the meaning of which is 
not very evident, although from its relation to the lateral parts of the ethmoidal carti- 
lage it is very probably a rudimentary “ pars plana.” As the section is close behind the 
“ internal nares,” a fold is seen in the mucous membrane on each side of the palate. 
The next section (Plate VI. fig. 4) has been made through the hemispheres (C l 4 ), the 
eyes (e.), and the middle of the temporal muscle (t.m.). The manner in which the barge- 
shaped skull of the Frog is formed, anteriorly, is well seen in this section ; for here the 
elongated pituitary space is bridged across ; a concavo-convex plate of cartilage, repre- 
senting the presphenoid ( p.s .), and underlain by the “ parasphenoid ” (pa.s.), occupies 
the mid line. 
Laterally, also, the trabeculae (tr.) are growing gently upwards around the membra- 
nous brain-sac, and will soon form the cartilage of the orbito-sphenoidal region. 
The suspensorium has been cut through close in ffont of the fossa for the stylo-hyal 
condyle, it is therefore the quadrate (pi.) ; the hinder part of the orbitar process is also 
seen (or.p.). This section has been made through the hyoid cornu (hy.), close in front 
of the condyle ; the manner in which these secondary (segmented) bars imitate those 
immediately in front of them is well shown (compare fig. 3 ,mk., and fig. 4, It?/.). Here, 
however, we encounter an additional element not seen in the mandibular arch, namely 
a basal azygous piece; this is the basihyal (b.h.); it is pear-shaped in section, the thick 
part below, and is composed of soft cartilage. This is a back view, and would seem to 
show that the hyoid cornua (hi/.) were extremely solid. 
A front view (fig. 4“, hy., b.h.) corrects this, however, and the plate is seen to be curi- 
ously sinuous and thin at parts. I shall not wait to describe ’the muscles which arise 
from the arch and which have partly beeii figured. 
The next section (fig. 5) is the front view of a solid slice made through the “mesen- 
cephalon” (C 2) and infundibulum (inf.) ; the razor passed close in front of the auditory 
capsules (pro.), behind the basibranchial (see Plate V. fig. 5, b.br.), and in front of the 
pericardium (p.c.d.). 
Here is the upper part (the so-called origin) of the temporal muscle (t.m.), the fibres 
being attached to the anterior face of the auditory capsule and to the upper surface of 
the “metapterygoid connective.” 
The Gasserian ganglion (5) is seen lying on that band close inside the anterior face of 
the auditory capsule ; its fibres pass over and in front of this mandibular root. The 
cartilage of the ear-capsule (pro.) is seen to be ascending on each side of the cranial 
sac; behind this view it is the pterotic, in front it is alisphenoidal. With regard to the 
