OF THE MARSIPOBRANCH FISHES. 
449 
(tr.), now distinct, but tilted, ready to begin the side walls of the skull in the etlimo- 
presphenoidal region. The hinder blind end of the budding “ posterior nasal canal ” 
(p.n.c.) is cut across; in fig. 6 a , (36 diams.), the lining of this pouch is shown to be 
composed of round cells. 
9th Section (partial; Plate 26, fig. 7).—This section is through the fore brain (C 1 .), 
and the fore part of the eye-balls (e.). The trabeculae (tr.) are now short-oval in 
section, and are tilted inwards, above. 
10 th Section (partial; Plate 26, fig. 8).—This is through the middle of the eye-balls 
(e.), and is quite similar to the last. 
11 th Section (partial; Plate 26, fig. 9).—This is through the mid brain (C 2 .), the 
back of the eye-balls (e.), the fore part of the Gasserian ganglia (V.) and of the noto¬ 
chord (nc.). Here the trabeculae (tr.) are sharp above, and inturned; they are a con¬ 
siderable distance from the apex of the notochord (see Plate 19, figs. 4, 5). 
12 th Section (partial; Plate 26, fig. 10).—This is the first section through the hind 
brain (C 3 .); it also passes through the fore part of the auditory capsules (au.), just 
behind their front face. There is here a rudiment of the alisphenoidal wall cresting 
the capsules on the inside, and their inner wall is complete, as this is in front of the 
“meatus ; ” externally, part of the shell of the fore face of the capsule is drawn. The 
cartilages (iv.) now approach the notochord (nc.), and they are winged at this point; 
the wings are the pterygo-pedicles (pd., pg-), which arch gently over the buccal 
cavity and thicken, externally. 
13 th Section (partial; Plate 23, fig. 8).—Here we lose the alisphenoidal crest, and 
the transverse facial outgrowths ; the inner wall of the capsule (au.) is still perfect ; 
the basal plates or parachordals (iv.) are oval in section. 
14 th Section (partial; Plate 23, fig. 9).—This is through the meatus internus or 
internal auditory fenestra through which the 8th nerve passes. It also shows the 
partial junction of the capsules with the parachordals (au.,iv.) ; those bands are 
now of a considerable height, and are nearer the enlarging notochord (nc.). 
15 th Section (Plate 26, fig. 11).—By comparing this section with the dissected skull 
(Plate 19, figs. 4, 5) and basket-work (Plate 25, fig. 8), everything skeletal can be 
identified. It is close to the back of the head, the ganglia of the vagus (X.) are cut 
through, and also the narrow tracts of the basal plates (iv.) lying against the large noto¬ 
chord (nc.) ; the hind brain (C 3 .) still comes into view. This shows the 1st branchial 
pouch (br.p 1 .) hi simple outline—the 1st branchial opening (e.b.a.) and the loop of 
cartilage (ex.br.) enclosing it in front of the 1st extra-branchial. 
We are now in the front region of the “ arclienteron,” which is a generalised pharynx 
(phx.) permitting the passage of both the food and of the water currents into the 
pouches. 
16 th Section (Plate 26, fig. 12.)—This is through the back part of the 1st 
branchial pouch and the extreme end of the hind brain (C 3 .). There is no para¬ 
chordal cartilage at this part, and the top of the 1st extra-branchial arch (ex.br.) 
