162 
MR. W. K. PARKER OR THE STRUCTURE AND 
Section 6 (Plate 23, fig. 6).—This large partial section is through the back of the 
eye-balls (e), the front of the cerebral hemispheres (0 la .), and the hind part of the 
nasal labyrinth. The perpendicular ethmoid (p.e.) is, as in the last, a wall standing 
alone, rounded, but thinnish above, thick and bulbous below 7 ; at present, the whole roof 
of the labyrinth, or floor of the cranial cavity at that part, is void of cartilage; there 
are two nasal passages (n.p.) on each side, and between them the rudimentary middle 
turbinal is growing. The floor of cartilage is imperfect below; the wall ( al.e) passes 
into the orbitosphenoidal lamina, above, and there is a fissure more than half-way 
down. The raphe formed by the meeting -together of the right and left palatal 
laminae is strengthened, still, by the palatine plate of the palatine (pci.) ; a wide, 
but not deep passage (n.p.c.) is seen above this second floor. The root of the tongue- 
(tg.), tooth-pulps, and the dentary bone (cl.), with Meckel’s cartilage (mJc.) inside it, 
are all shown in the lower part of this section. 
Section 7 (Plate 23, fig. 7).—Here the cerebral hemispheres (C la .) are large, and the 
wide orbitosphenoids (o.s.) form the floor of the cranial cavity; they are continuous 
with the presphenoidal bar ( p.s.), which is oval, with the long diameter transverse. 
The wings themselves (o.s.) are thinner and then thicker, twice over. This section is 
diagnostic of a Eutherian skull; the alisphenoid (al.s.) comes into the same section with 
the orbitosphenoid (o.s.) lying outside it, and the} 7 have the Gasserian ganglion (Y.) 
between them. Here the pterygoid bones (pg.) are cut across, and the little nodule 
of cartilage, which becomes the pterygoid ( pg.c.). We also see the undiminished 
Meckelian rod (rnlc.) with the growing ramus of the lower jaw (d.) outside it. The 
large nasopalatine canal is constricted in the middle, and has the ceratohyals (c.hy.) 
in section below it. 
Section 8 (Plate 23, fig. 8).— This section is through the fore part of the basi- 
sphenoidal bar (b.s.), close behind the presphenoid ; here it has been formed by the three 
trabecular bars, the hind part of the intertrabecula wedging in between the paired 
trabeculae. 
The angle of the orbitosphenoid (os'.), and part of its lower hind margin, has been 
cut through ; this latter band is, however, far from the basal beam ; it lies over the huge 
Gasserian ganglion (V.), the fore part of which is here seen in section ; this mass lies on 
the out-thrust alisphenoid (al.s.) which is hollow above, and has a thick upper edge. 
On the inside of each alispthenoid the upper part of the corresponding pterygoid is 
cut across, and below the alisphenoid is the lower jaw or dentary (cl.) developing 
outside Meckel’s cartilage (mk .); it is an oblique long oval tract, hollow in the inside 
where the rod of cartilage lies. The wide nasofaucial passage is constricted at its 
middle ; below it, part of the larynx is seen, and on the outside the ceratohyal (c.hy). 
Section 9 (Plate 23, fig. 1 2)3'—This section is directly in front of the pituitary body 
and sella turcica ; and here the alisphenoid is cut across, where it runs near the 
* The re-arrangement of most of these figures as half-sections, so as to get them into a smaller space, 
has produced some confusion; the figures do not always follow in regular succession on the Plates; but 
the numbers give the correct order, except in this instance. 
