108 
MR. W. K. PARKER OjN t THE STRUCTURE AND 
converging arcuate ridges, a large canal is seen, occluded in its middle by the largest of 
four or five swellings of cartilage, that thus clumsily, as it were, have resoldered the 
trabeculae together. Looking at the upper view (Plate VIII. fig. 1, al.s.), we see feeble 
attempts at the formation of “ aliethmoidal ” and “ aliseptal ” laminae; but the “septum 
nasi” only exists as the clubby coalesced “ trabecular horns.” Above, the cartilage near the 
mid line is imperfect ; then, behind that, we see a piece of the “lamina perpendicularis ” 
(p.e.) crop up to the surface, and behind this the opening which is the anterior remainder 
of the “ great fontanelle,” overhung by the free fore end of the “ culmen cranii.” This 
remnant of the “ fontanelle,” and the vacuity a little in front of it, both open into the 
great mesoethmoidal fat-cavity (Plate VII. fig. 4, m.n.c.). Is there any morphological 
meaning in this fat-cavity, and in these deficient solderings of the “ trabecula; cranii ” in 
front of the cranial cavity 1 
If the reader will refer to the fourth Plate in Joh. Muller’s magnificent work on the 
Myxinoids (‘ Vergleichende Anatomie der Myxinoiden he will be able to answer this 
question for himself ; meantime I will refer him to the sectional views of this Salmonine 
remnant of the azygous nasal sac of the Myxinoid with its “ Nasenoffnung” above and 
its “ Nasengaumenoffnung” below (see Plate VII. figs. 4, 7, & 8, m.n.c.). 
The facets for the palatines are not on the widest part of the ethmoidal region; for, 
above, the huge “ ectoethmoidal ” wings form both wall and roof to the orbit in front, 
and, largely ossified, they form the so-called “ prefrontals ” (Plate VIII. figs. 1 & 2, and 
Plate VII. figs. 1, 2, 3, & 9, l.e.). These elegant shelving ethmoidal wings are sepa- 
rated above by a notch from the “ mesoethmoidal ” region, which has at that part 
become the “ culmen cranii.” Exactly between these antorbital expansions the “ meso- 
ethmoid” is, as has just been stated, occupied by fat, but further backwards it reappears 
a veritable “ lamina perpendicularis ” (Plate VII. figs. 4 & 9, p.c.). Outside the fat-cavity 
the antorbital wall is pierced by the “olfactory crus ” ( i ) ; in the lateral view (Plate VII. 
fig. 3, i) this can be seen emerging from the orbito-sphenoid behind, and reappearing in 
front of the “ ectoethmoid ” in the recess for the “ nose-capsule.” The ridge above this 
recess is the rudiment of the “ aliethmoid ” of the Bird and other high types, and the 
ridge below is the edge of the “ subnasal lamina” of the Frog. 
If the reader will refer to my paper “On the Fowl’s Skull” (Plate lxxxvi. figs. 8 & 9), 
he will see that the “ prefrontal ” bone answers to the region called “ pars plana,” the 
seat of the “middle turbinal,” whilst the upper unossified part of the lamina is the 
counterpart of the foundation for the “ upper turbinals.” Of course there can be no 
“ inferior turbinal,” as there is no specialized “ septum nasi ” from which it could grow 
as an outgrowth from an “ aliseptal lamina.” 
The Fowl gives voice as to the meaning of the “ culmen cranii;” I had described the 
retral continuation of the ethmoid along the mid line, above the olfactory groove, as the 
“crista galli,” but corrected this error (see “Fowl’s Skull,” note to p. 762, and Plate lxxxi. 
figs. 3, 4, & 5, eth.). If this elegant roof had continued its growth backwards in the 
Fowl instead of degenerating into a spike, we should have had what does appear in the 
