anterior end of this prolongation approaches, or even overlaps, externally the hind end of th e meseth-
moid The la te ra l portion of th e prolongation supports, on its dorsal surface, the mesial edge of t e
posterior portion of th e nasal. The nasal is a relatively large, flat, subrectangular bone, traversed
its full length by th e supraorbital latero-sensory canal. The posterior portion of the bone forms the
roof of th e nasal pit. The anterior portion of the bone rests in p a rt upon th e dorsal surface of the
anterior prolongation of th e frontal, in p a rt upon the dorsal surface of th e mesethmoid and m p a rt
closely upon th e cartilage of th e anterior end of the snout: and this anterior portion of the nasal pre-
sents th e appearance of being composed of an underlying membrane component fused w ith an overlying
latero-sensory component. Be this composition of th e bone as it may, th e two parts may be referred
to for th e p resent descriptive purposes, as th e m embrane and latero-sensory components of the bone.
Themembranecomponentprojects slightly beyond th e anterior and mesial edges of th e anterior end of
th e latero-sensory component, there resting upon the cartilage of th e snout. Along th e lateral edge of the
bone this membrane component tu rn s downward, and so forms a lamina-shaped process w hich projects
ventrally along th e lateral edge of the cartilage o fth e sn o u t; and this lamina-shaped process would seem
to be th e homologue of th e process, na’ described by Swinnerton on th e nasal of Gasterosteus. Its
ventral edge extends to, oris even more or less interposed between, the anterior end of th e p alatine and
th e cartilage of th e end of th e snout, this process of th e nasal th u s seeming to form p a rt of th e
articular surface for th e anterior end of th e palatine.
In two of my specimens of Belone th e membrane component of the nasal was easily detached,
in p a rt or in whole, from th e overlying portion of the bone; and although this may have been due
to a partial disintegration of the bone, due to th e fact th a t my specimens had been long preserved in
alcohol and h ad then been boiled, it would ten d to indicate th a t the p a rt of th e bone th a t so separated
was an independent ossification. I t is a strictly and evidently ectosteal bone, and hence can not
represent, in any part, th e bone described by Swinnerton as th e preethmoid, which bone he classes
as „undoubtedly endosteal“ .
Immediately anterior to the anterior end of th e palatine, there is, on th e lateral edge of the
cartilage of th e snout, a small b u t marked eminence not shown or described by Swinnerton but
which must be th e preethmoid cornu of th a t author’s nomenclature notwithstanding th a t it forms
no p a rt of the articular surface for the palatine. The ventral edge of the laminar process of th e nasal
reaches th e base of this little process, b u t does n o t extend upon it; and between the cartilaginous
process and th e lateral surface of th e laminar process, there is a groove w hich receives th e dorso-mesial
edge of the maxillary bone, the la tte r bone articulating in p a rt with th e cartilage here, and m p a rt
with a small articular surface on th e laminar process of th e nasal. The maxillary thus here articulates
with th e dorsal surface of th e snout, and, furthermore, p a rtly with an apparently m embrane component
of th e nasal bone, which component thus seems to here replace th e preethmoid, and may perhaps
represent th a t bone. This membrane component of the nasal also somewhat resembles bone 2 oi
Huxley’s descriptions of Esox, and it may b e th e homologue of th a t bone and n o t of the preethmoid;
this th en applying also to th e process na ’, of the nasal of Gasterosteus. This needs more careful investigation
th a n I have been able to give it, b u t it is evident th a t as the vomer has no dorsal limb,
th e preethmoid, if n o t absent, must be elsewhere represented.
The palatine of Belone is said by Swinnerton to articulate with th e cranium a t its anterior end
only, the posterior articulation being said to be wholly absent. This certainly is not tru e of m y specimens.
Here the lateral wing of the antorbital cartilage is n o t entirely occupied b y th e ectethmoid
Bone, the cartilage extending ventrally beyond th e bone, and its ventro-lateral end projecting as a
small process which certainly gives articulation to the palatine cartilage a t or near its hind end. Between
this articular surface and th e surface th a t gives articulation to the anterior end of the palatine,
th e dorsal edge of th e palatine cartilage approaches closely a narrow longitudinal ridge on the ethmoid
•cartilage, is strongly attached to it by fibrous tissues, and would seem to be in contact with it. The
anterior end of th e palatine lies against th e internal surface of the maxillary, posterior to th e articular
surface on th e dorsal edge of th a t bone, and posterior also to the little preethmoid cornu.
Belone, it may here be stated, presents certain peculiarities in the d istribution of its latero-
sensory canals. There is, in th is fish, as is well known, a ventral body line, with a short branch line
running upward slightly in front of the pectoral fin. What is not known, so far as I can find, is th a t
th e re is a canal in the premaxillary, this canal apparently being an anterior and independent section
of th e infraorbital line, which extends forward, from the base of th e bone, through about one third
o f its length. There is no slightest indication, on the external surface of the premaxillary, of a fusion
of latero-sensory ossicles with an underlying tooth-bearing bone; b u t th e evident supposition is th a t
such a fusion has taken place, th e latero-sensory ossicles, of either side, together representing the
•ethmoid of Amia and th e supraethmoid of Salmo (Parker, ’73), and each ossicle here being fused
with the corresponding premaxillary to form th e ascending process of th a t bone. A cartilaginous
Tostral is held between th e hind ends of th e premaxillaries, as it is, in Scorpaena and many other
fishes, between the ascending processes of those same bones.
A further p eculiarity of th e latero-sensory system of Belone is, th a t from the point in the frontal
where, in other fishes th a t I am familiar with, the penultimate tube of the supraorbital canal arises
from th a t canal, the canal in Belone seems to separate into two parts. One of these two parts turns
latero-posteriorly, traverses th e pterotic, and seems to end a t the hind end of th a t bone. The other
p a rt continues posteriorly to the hind end of the frontal, and there runs directly into what seems to
be the antero-mesial end of the supratemporal canal, which canal then continues backward as the m ain
■canal. If th e bone here traversed by th e supratemporal canal is an extrascapular bone, as its relations
to the canal would indicate, a parietal bone would seem to b e lacking. These conditions are so unusual
th a t I am collecting and preparing m aterial for a proper study of them.
Returning now to th e vomer, it may be said, th a t in all cases where an independent preethmoid
bone has been properly identified, the vomer has no ascending processes, and is confined to the ventral
surface of the chondrocranium; and th a t in the Acanthopterygii and Anacanthini, in which fishes a
preethmoid has never been described, the figures and descriptions of the vomer show certainly th a t
i t usually has, and it seems probable th a t it always has, a dorsal limb. In other fishes the descriptions
and figures are much too indefinite to w arrant a serious a ttem p t a t comparison. I t may, however,
be s tated th a t, in a general way, and so far as can be judged from th e ra the r indefinite existing figures
and descriptions, th a t where the maxillary has th e relation to the premaxillary th a t Sagemehl de-
.scribed as lateral (the m axillary lying as a postero-lateral continuation of the premaxillary), the vomer
has no ascending processes, and th a t where the maxillary has the position described by Sagemehl as
posterior (internal) to th e premaxillary, the vomer has those processes. The maxillary is found
lateral to the premaxillary, according to Sagemehl (’84b, p. 101), only in a few families of the Physo-
stomi, those few families of fishes accordingly probably being the only ones in which the vomer is
without ascending processes. The maxillary is, according to Sagemehl, never found toothed excepting
in those same few families.