OF THE MARSIPOBRANCH FISHES. 
393 
shown. The bar cut through is hyomandibular above (just where the opercular process 
is given off in Teleosteans), and symplectic ( sy .), below. Inside the bar the 1st 
pharyngo-branchial ( jp.-br 1 .) is still hard. The opening of the naso-palatine canal 
into the pharynx ( phx .) is very wide here, and the round folds right and left are the 
sides of the “ velum” ( vl .). The basi-hyal { h.hy 1 .) is beginning now to lose its hard 
cartilage ; the soft cartilage at its edges is the distal part of the descending hyoid 
bar, the hypo-hyal region. 
Section 30 (Plate 14, fig. 7).—The ends of the auditory capsules are here cut through, 
and the investing mass {iv.) is now a thick trough, in which the enlarging notochord 
lies. The lateral cartilages {sy., jp.br 1 .) are the same as the last, but cut through a little 
further backwards. The double basi-hyal now passes into the large soft elastic 1st basi- 
branchial above the hard paired cartilages {b.hy 6 .). The soft end of each descending 
hyoid bar {h.hy.) is seen cut across. 
Section 31 (Plate 15, fig. 1).—This section is very similar to the last, but is behind 
the auditory capsules, and the investing mass {iv.) is lesser, whilst the notochord {nc.) 
is larger. Below, the hard cartilage of the basi-hyals grows for some extent into the 
1st basi-branchial {b.h.br.), the hypo-hyal end of the cerato-liyal bar {h.hy.) is still 
seen; it is slightly confluent with the basal bar. 
Section 32 (Plate 15, fig. 2).—The notochord is now two-thirds of its average sjnnal 
thickness ; it is almost enclosed by cartilage ; this and the last are in the occipital 
region in front of the 1st spinal nerve (Plate 9, figs. 1, 2, sjp.n.) ; here the hind brain 
(C 3 .) begins to be myelon. The large flat symplectic region {sy.) still comes into 
section ; above it is the inter-hyal bar {i.hy), and, within it, the 1st pharyngo-branchial 
{jp.br 1 .). Below 7 , the hypo-hyal is seen to be distinct from the soft elastic 1st basi- 
branchial ( b.br b), the section of which is LJ-shaped and thick. The form of the two- 
lobed velum {vl.) is well shown here, with the open channel in which the naso-palatine 
canal ends. 
Section 33 (Plate 15, fig. 3).—The notochord (nc.) has now acquired nearly its full size, 
and still it has two points of cartilage upon it, the extreme ends of the parachordals 
(see figs. 1, 2, iv.). A good distance down we get the upper band of the branchial 
basket-work cut through where the outer descending hyoid passes free from the hyo¬ 
mandibular region ; this is the inter-hyal region {i.hy.). This bar re-appears again 
below at the bottom of the cerato-hyal as the hypo-hyal region {h.hy.); in some of 
the sections not drawn these two points passed into each other, the compression of the 
head curved the bar so as to make the razor pass through it in two points ; and the 
same cause has forced the “ velum ” down, so that both in this and the next, the carti¬ 
lages in it {p.br l .,p.b?' 2 .) are lower down than in an undisturbed state. Between these 
small points we see the leafy part of the symplectic (see Plate 9, figs. 1, 2, sy.), still 
coming into view in section. The 1st basi-branchial {b.br 1 .) is now a deep trough of 
vacuolar tissue, with the hypo-hyals {h.hy.) at its edge. 
Section 34 (Plate 15, fig. 4).—This is from a considerable distance back, so that all 
