ETJGNATHIDJE. 
289 
plates. There are two very large suborbitals (or postorbitals) 
immediately in front of the preopereulum, and there is a circum- 
orbital ring of small plates of irregular size. At least one large 
preorbital plate may also be noticed. The maxilla is comparatively 
robust, long and narrow, somewhat deepened behind and with a 
stout inwardly directed process near its anterior extremity. Its 
hinder margin is excavated by a sharp re-entering angle, and the 
oral margin is straight or slightly concave. Above the posterior 
half of the bone is a long narrow supramaxilla, which is pointed in 
front but truncated behind. The premaxilla is antero-posteriorly 
extended, not deepened, but with a short narrow process rising 
upwards near the middle of its superior border. The hyomandi- 
bular is elongated, much laterally compressed, and with a large 
process for the support of the operculum. Its long axis is only 
slightly arcuated, and its expanded lower extremity meets both the 
quadrate and the symplectic. The latter is an elongated triangular 
bone, its narrow base turned upwards in contact with the hyoman- 
dibular, its thickened apex apparently extending to the articular 
condyle of the quadrate. The entopterygoid is a large laminar bone 
covered on the oral face by minute granulations resembling those 
of the parasphenoid. The ectopterygoid and palatine are not 
certainly known. The mandible is much deepened in the coronoid 
region, but the limits of the coronoid bone are rarely observed; it 
is shown in the original of fig. 34, p. 293. The angular element 
is of moderate size, meeting the dentary in a wavy suture in the 
coronoid region. The dentary itself also rises in the front part of 
this elevation, but rapidly tapers and becomes very narrow at the 
symphysis ; it bears a single series of large conical teeth. The 
splenial, also partly extended into the coronoid elevation, is a thin 
laminar bone behind, but much thickened in front, where it enters 
and strengthens the mandibular symphysis. Its teeth are all 
minute, those in its hinder portion being mere granulations. The 
ceratohyal is very large, deep and laterally compressed behind, but 
apparently depressed in front so that its inferior border exhibits a 
narrow flattened horizontal expansion. The triangular epihyal is 
small and thin ; the hypohyal on each side is a still smaller, but 
square and much thicker bone. 
The branchial arches are delicate and exhibit the channel 
specially characteristic of modern bony fishes. They bear a much¬ 
spaced series of large slender gill-rakers, which are straight and 
acutely pointed. The basibranchials are slender. The opercular 
apparatus is complete : the branchiostegal rays are laminar; and 
PART III. it 
