544 
ME. W. K. PAEKEE ON THE STEUCTTJEE AND DEVELOPMENT 
The series of sections (Plate 23. figs. 3-8 and Plate 21. figs. 8-10) will help to illustrate 
the present condition of both face and skull. 
The first (Plate 23. fig. 3) is through the fore brain (C 1 ) and nasal sacs ( ol .). Two 
pairs of bony plates are cut through the vomers ( v .) inside the nasal capsules and the 
dentaries ( d .) near the chin. 
The second (Plate 23. fig. 4) was made through the front of the mid brain (C 2 ) and 
eyeballs. There is no cartilage in the upper lips and cheek, but the terete ends of the 
trabeculae ( tr .) are severed. These have the palatine toothed plate attached. 
Below, Meckel’s cartilages are similarly protected on their inner face by the 
splenial (sp.). 
The next section (fig. 5), half of which is shown, is a little behind the last, and shows 
the orbito-sphenoidal crest of the trabecula (tr.). 
The fourth section (fig. 6) is through the back of the eye and mid brain ( e ., C 2 ). In 
its sensible thickness both the position of the pituitary body ( py .) and of the apex of the 
notochord ( nc .) are shown. 
Here the alisphenoidal crest of the trabecula is at its highest. J ust in front of the 
mandibular pier the temporal muscle is seen to pass from this crest to the crested 
coronoid region of Meckel’s cartilage (wrongly lettered g). The transverse floor of 
the mouth shows seven cartilaginous rods in section. Those near the mouth-angle are 
the hyoid cornua ( c.hy .), and the cluster in the middle are the first cerato-branchials out- 
side (c.br. 1 ) ; the second cerato-branchials above and within ( c.br 2 ), and the second 
basibranchial below, at the mid line ( b.br . 2 ). These rods are seen in a full-sized Peren- 
nibranch in Plate 25. fig. 5 : that figure will explain the position of these sections. 
In the fifth section (fig. 7), a little further back, the notochord (nc.) is cut through, 
and we see the descending part of the alisphenoidal crest of the trabecula (tr.). Here is 
seen the great height of the ascending process of the mandibular pier (a.p.) and the 
stunted pedicle. Below these the orbito-nasal nerve is seen cut through. 
The pier (q) then descends, thick and solid, to the articular region. The free 
mandible escapes this section, and the flattened upper part of the hyoid (c.hy.) is 
severed. 
The second basibranchial (b.br. 2 ) is now flattening towards its hind part, and the 
first two branchials (c.br. 1 , c.br. 2 ) are cut through close to their epihyal region. 
The sixth section (half) is through the front of the ear-capsule and hind brain 
(fig. 8, an., C 3 ). The trabeculae and Gasserian ganglion are shown (tr., 5), the otic 
process of the “pier” (ot.p.), the hyoid cornu (c.hy.), and an oblique slice is seen of 
the first epibranchial (e.br. 1 ). 
The seventh (Plate 21. fig. 8) is through the middle of the hind brain and auditory capsule 
(C 3 ). Then we have a section of the apices of the trabecular plates at the first third of 
the notochord (nc., tr.). The outer and lower part of the ear-capsule is chondrified, 
and the anterior and horizontal canals are severed ( a.s.c ., h.s.c.). 
An apparently meaningless cavity, lanceolate in section, is seen in this and the next 
