DEVELOPMENT OF THE SKULL IN THE SALMON. 
107 
from beneath, we see two symmetrical cartilaginous slabs, totally unossified, which 
together form a rough kind of cross deeply grooved along the mid line, for it has its 
equal moieties bevelled towards the middle. These moieties were formed of the fiat 
tape-like trabeculae, which met each other at an obtuse angle, so as to present a ridge 
towards the overlying membranous cranium. They were bowed out far beyond the 
boundary of the pituitary body, and by the end of each bowed part they coalesced 
with the corresponding moiety of the investing mass ; now, however, there is no such 
connexion, the trabeculae are again free , and they end by two small points with a 
rounded emargination between (Plate VIII. fig. 2, tr.). Each free point is the termina- 
tion of a lanceolate convexity, and these convexities diverge in front, terminating on the 
outer edge of the trabeculae. These facets have relation to the underlying “ parasplie- 
noid;” for here the flat part (Plate VII. fig. 2, pa.s.) becomes carinate above, and also gives 
off the “ basitemporal aim.” But these facets have another meaning than their relation 
to the parasphenoid ; for they are the first budding (arrested, indeed, and functionless) of 
the “anterior pterygoid processes” (see “Ostrich’s Skull,” Plate vn. fig. 4, a.])., and 
“ Fowl’s Skull,” Plate lxxxiv. fig. 11, a.p.). These processes are the “ basipterygoids” of 
Huxley (seeProc. Zool. Soc. 1867, p. 418). Another pair of facets are formed beneath 
the arms of the cross ; these are for junction with corresponding facets on the palatal bar ; 
at these points the trabecular skull-base becomes greatly expanded. Corresponding with 
what I have said in my account of the development of the Frog’s Skull, I call these 
outstanding parts, that tend to make the facial arches into a kind of basketwork, like the 
gill-crate of the Lamprey, the “ facial connective growths.” Those by which the palato- 
pterygoids join the trabecular bars appear during my rather long “first stage;” but 
those which foreshadow the second pair of connectives in the “ Sauropsida” cannot be 
seen until the metamorphic changes are well nigh over. 
Having sent out the “palatal connectives” the trabeculae gradually contract : the part 
in front of the palatal connectives may be called the “cornua trabeculae between 
those projections we have the transverse partition formed between the eyes and nose- 
sacs, whilst the further continuation of the trabeculae is modified in relation to the nasal 
organs. The broad part immediately in front of the facets is the floor of the nasal sacs, 
and corresponds to the “ subnasal lamina” of the Frog (“ Frog’s Skull,” Plate vn. fig. 6, 
s.n.l. ). Below, this is traversed by a curved ridge, which grows towards its fellow, ante- 
riorly, in an elegant lyriform manner ; the two do not meet at the mid line, but in front 
of them the thick short trabecular horns unite their substance, have a groove between 
them, and end in a bevelled facet ; each “ horn ” is separated from its fellow at the end 
by a rounded emargination. Moreover, each horn has at its tip a pair of short, thick 
upper labial cartilages (u.l. a , u.l . b ), the inner of which is the largest; they are joined 
by fibrous tissue, but they have a joint cavity between themselves and the “horns.” 
Between the nasal sacs the trabeculm are badly soldered together ; in front the cartilage 
loses its substance in places, which becomes replaced by fat; further back, however, 
there is a large, apparently meaningless, cavity, filled also with fat. Below, between the 
