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MR. W. K. PARKER OK THE STRUCTURE AND DEVELOPMENT 
(d.) These labials are shown in situ in the same figure, which shows the nasal roofs 
from below, with the underlying parts. 
The first labial is pointed in front : this is free or coalesced with the corresponding 
trabecular cornu, it then becomes wider, diverges, and becomes pedate and sub- 
bifurcate. 
This first labial keeps along the suture, between the septo-maxillary above, and the 
vomer below (Plate 32, figs. 2, 3, and Plate 33, figs. 2, and 5-9, u.l 1 ., sm.x., v.) ; it reaches 
the opening between the two bones for the duct of the nasal gland ( n.g .). 
The second upper labial (u.l 2 .) is a broader cartilage ; its external part, which acts as 
a valve to the opening for the duct, is oblong, but the band is carried inside the capsule, 
and then ends in a rounded lobe (Plate 33, fig. 10, also figs. 2, 9, 11, 12, 15, and 16 ; 
and Plate 32, figs. 2, 3). 
(e.) The azygous bone attached to the nasal region is the premaxillary (px .) : it has 
a somewhat angular anterior margin, a short, blunt nasal process (Plate 32, fig. 1, and 
Plate 33, figs. 1, 2), an edentulous edge, and two short, rounded palatine processes 
(Plate 32, fig. 2). 
The nasals (n.) imperfectly cover the roof, their upper surface (Plate 32, fig. 1) is 
roughly triangular, and they send down a vertical plate between the cartilages, the 
right and left plates lying back to back ; these plates are deeper than the septum 
nasi (Plate 33, figs. 1 and 6-12, n., s.n.). 
A stout shell of bone, having a lozenge-shaped outline, lies over the outside of the 
olfactory cartilages ; this is the prefronto-lachrymal (p-f-). It has the character, and 
supplies the place of both those bones ; by this the orbital rim is finished in front, and 
to the lower process of this bone the maxillary is attached, especially in venomous 
Snakes. 
If this bone had grafted itself upon the cartilage, it must have been called the 
prefrontal or ecto-etlimoid ; it is, however, as free as the ordinary pre-orbital or 
lachrymal. 
Nothing that has come under my notice in cranial morphology shows a more 
curious or a more elegant architecture than the form pre-palatal bones now to be 
described. 
The upper pair are the so-called inferior turbucals of older authors ; but the Snake 
has no inferior turbucals, and when these exist, they are not membrane-bones, but 
cartilages, soft, or more or less ossified, that grow as outgrowths from the inner face 
of the nasal wall, and run from the inside of the outer nostril downwards and backwards 
to the “ choana ” or “middle nostril.” 
Those outgrowths are largely developed in Birds and Mammals, and I find a rudiment 
of them in Chelone mydas , and in Lizards. 
But these bones form a floor to the nostrils ; they are found in both Urodeles and 
Anourous Batrachia ; and if those of the Lizards — the Varanians especially — be com- 
pared with that pre-orbital bone of Ganoid and Siluroid Teleostean Fishes, which 
