end of the maxillary process of th e palatine. I t does n o t give support, a t any point, to the lachrymal;
b u t a short, strong ligament extends from th e summit of th e ascending process of th e bone to the
dorsal edge of th e lachrymal, this ligament having its attachment also in p a rt on the lachrymo-palatine
process of th e nasal.
The LIGAMENTS associated with the upper jaw were n o t properly investigated, th e smaller
specimens not being suitable for this investigation, and th e skeletons of the larger specimens having
been prepared, as already stated, without special attention being given to any of the soft parts. The
ethmo-maxillary ligament is well developed, even in th e small adults, and has already been described.
The rostro-palatine ligament is also well-developed and has th e usual relations, but, because of the
shortening and deepening of th e snout, it lies in a nearly horizontal position, th e position being the
more n early horizontal, the smaller th e specimen. The tendon of th a t p a rt of the adductor mandibulae
muscle th a t has its insertion on th e maxillary in the other fishes of the group, is here also well developed,
a n d , the posterior portion of th e ligamentary process of the maxillary n o t being developed,
is inserted on the dorsal surface of th e body of th e bone near its proximal end. The naso-maxillary
ligament is a short s tout ligament th a t extends from the lachrymo-palatine process of th e nasal to the
outer end of th e ascending process of the maxillary. The vomero-palatine and lachrymo-palatine
ligaments are reduced, because of th e articulating contact of th e pa rts concerned, to tough fibrous
or ligamentous tissues th a t hold th e articulating surfaces together. No other definite ligaments
were recognised in th e dissections, b u t in th e sections of th e small specimens there is a well developed
ligament th a t extends from th e lateral surface of th e rostral to the dorsal end of th e ascending process
of th e maxillary; and another th a t extends from the ventral (here posterior) edge of th e ascending
process of the premaxillary to th e proximal end of the maxillary, this ligament traversing the narrow
space between th e rostral and th e articular process of th e premaxillary.
The VOMER differs somewhat from th e bone in th e other fishes of th e group, and it can
be b est understood b y stating, a t once, th a t this p a rt of th e skull of D actylopterus has been so greatly
flattened th a t th e ascending processes of th e vomer have apparently been pressed down upon and
become completely fused with th e underlying body and lateral processes of th e bone; th e antorbital
cartilage being, so to speak, squeezed out from between th e dorsal and ventral limbs of the bone.
As a result of this, th e vomer is a solid bone of th e shape shown in th e figures, with a convex ventral
and a concave dorsal surface, the exposed portion of th e la tte r surface being about two-thirds as
long as the ventral surface of th e bone, and representing th e ascending processes of th e bone. This
p a rt of th e dorsal surface of th e bone forms th e floor of th e anterior portion of th e rostral chamber,
is grooved in th e middle line to receive th e rod-like prenasal process of the antorbital cartilage, and,
lateral to th a t groove, on either side, has a slightly raised and flattened surface which gives articulation
to th e ascending process of th e corresponding maxillary. The middle portion of th e hind edge
of this p a rt of th e vomer abuts against th e anterior edge of th e antorbital cartilage, • b u t whether
it is in synchondrosis with th a t cartilage or not, could not be definitely determined. Apparently
it is not, th e vomer of Dactylopterus seeming to be a purely dermo-membrane bone, and not appreciably
overlapping or having perichondrial relations to th e dorsal surface of the adjacent cartilage.
Lateral to th e antorbital cartilage, on either side, the th in h ind edge of this p a rt of the vomer — here
apparently formed by th e fusion of the lateral and ascending processes — suturates with the pedicle
of th e corresponding ectethmoid, th e hind end of the short body of th e bone underlying th e antorbital
cartilage and suturating with the parasphenoid.
The head of the vomer is bent downward and thickened, as in the other fishes of the group,
this thickened portion forming a broad transverse b u t untoothed surface which extends across the
anterior end of the ventral surface of th e bone. The lateral ends of this dental b u t untoothed ridge
are concave or flattened, and give origin, on either side, to a very short b u t s tout vomero-palatine
ligament which has its insertion on the internal surface of the anterior end of the body of the palatine.
Beginning immediately lateral to the dental ridge, a t the anterior edge of the vomer, a slight ledge
extends postero-laterally across th e ventral surface of th e bone to its hind edge, and th a t small p a rt
of th e ventral surface of the bone th a t lies antero-lateral to this ledge lies a t a slightly deeper level
than th e remainder of the surface. The anterior edge of this little surface of the bone is rounded,
fits into a deep groove on th e internal surface of th e base of the maxillary process of the palatine,
and gives articulation to th a t bone; the ta ll posterior wall of the groove on th e palatine fitting against
the little depressed surface on th e vomer and the edge of this p a rt of the groove abutting against
the ledge on th e vomer and so limiting the inward swing of th e palato-quadrate apparatus. The
rounded articular edge of th e vomer is continuous with a similar edge on the pedicle of the ectethmoid,
th e la tte r bone apparently participating slightly in the articulation; this articulation thus certainly
containing th e anterior ethmo-palatine articulation of the other fishes of th e group, and apparently
representing th a t articulation alone. Posterior to the articular groove on the palatine, th e dorsal
edge of th e la tte r bone abuts against the ventral surface of th e pedicle of the ectethmoid and is bound
to it by tough fibrous tissue, this contact apparently representing the posterior ethmo-palatine articulation,
here practically suppressed.
The ECTETHMOID has a somewhat diamond-shaped and strongly convex external surface,
the dorsal and lateral surfaces of th e bone being inclined a t more th a n a right angle to each other,
and the lateral edge of th e bone being, in consequence, directed ventro-mesio-posteriorly. The
posterior edge of the bone is curved and slightly concave, is presented postero-laterally, and forms
the anterior portion of th e margin of the orbit. The mesial edge of th e bone forms two sides of the
diamond-shaped outline- of th e bone. The posterior one of these two sides is straight, is presented
postero-mesially and suturates with th e frontal; the anterior one suturating in its posterior half
with the nasal, while its anterior half is occupied by a deep, oblong incisure which forms the ventro-
antero-lateral boundary, and p a rt of th e dorso-postero-mesial boundary of the nasal opening. The
bent-under lateral edge of th e bone is slightly concave, th e concavity arching over the lateral edge
of a ta ll and flat articular eminence which begins a t this edge of the ectethmoid and extends mesially
and slightly posteriorly along the ventral surface of the bone. This eminence projects ventro-mesially
and gives articulation to a facet on th e dorsal edge of th e lachrymal.
Beneath th e curved external, and evidently purely dermal portion of the ectethmoid, the
deeper portion of th e bone extends into th e cartilage of the antorbital process, forming a sort of
pedicle to the external portion. The pedicle is directed ventro-mesially, and is p a rtly in synchondrosis
with the median remnant of the antorbital cartilage, and pa rtly in sutural contact with the vomer
and parasphenoid. The anterior surface of the pedicle is deeply hollowed to form p a rt of the bounding
wall of th e nasal pit, its posterior surface being less deeply hollowed to form p a rt of the anterior wall
of the orbit. In th e mesial edge of th e pedicle there is an incisure which, with the adjoining cartilage,
forms a foramen which transmits the olfactory nerve from the orbit to th e nasal pit.
The ORBIT is deep and low, with curved b u t nearly transverse anterior and posterior walls,
formed, as. usual, by the concave posterior surface of the ectethmoid and the anterior surface of the
Zoologica. Heft 57. 21