FISHES—HETEROLEPIDAE—OPLOPOMA PANTHERINA. 
47 
upon the superior posterior part of the orbit, being about three-eighths of an inch long and half 
as broad where broadest, inserted transversely, so as to lean backwards and slightly downwards 
along the orbit. The lower jaw is longer than the upper. The mouth is slightly oblique 
upwards and rather large, since the posterior extremity of the maxillary extends to a vertical 
line drawn somewhat posterior to the entire orbit. The jaws are furnished with canine teeth 
of different size ; the largest may be observed upon the branches of the dentaries and upon the 
vomer ; the next in size are on the premaxillaries and the palatines. All these are accompanied 
by small conical and acerated teeth, irregularly distributed over the bones upon which they are 
inserted ; a group of them may be seen on each side of the symphysis of the premaxillaries. 
The surface of the tongue is perfectly smooth, thin, and pointed anteriorly. The eye is well 
developed; sub-elliptical in shape; its longitudinal diameter entering about six times in the 
length of the side of the head. There are two nostril openings on either side, quite apart from one 
another ; the anterior, which is the largest, is situated in advance of the eye, being much nearer 
the orbit than the extremity of the upper jaw ; the posterior is placed upon the anterior supei'ior 
rim of the orbit. The convexity of the preopercle is provided with some short and obtuse 
spines, or rather obtuse processes, mostly hidden under the skin. The rest of the opercular 
bones are smooth and without spines ; the opercle has the shape of an acute triangle, with its 
summit pointing obliquely towards the back, having at its inferior edge a prominent subopercle, 
extending beyond .the summit of the opercle, and likewise in a very oblique position. The 
interopercle is also a well developed bone. The gill openings are very widely open, in the 
shape of an obtuse curve, extending beneath to the hyoide apparatus, and continuous from both 
sides. The branchiostegals are well developed, six in number, on either side. 
The anterior dorsal is nearly twice the length of the posterior, and a little higher upon its 
middle. It commences at a short distance from the occiput, in advance of a vertical line which 
would intersect the limb of the preopercle. It is composed of twenty-four spinous and acerated 
rays, the four anterior being shorter than the sixth and the following, simulating together an 
independent fin, though much less distinctly than in Heterostichus rostratus. The second dorsal, 
which is united to the first at its base, is composed of twenty-one articulated rays, with two 
rudimentary ones and a small spine upon its anterior margin, from which a membrane is sent 
to the posterior spine of the first dorsal. Most of the articulated rays of the second dorsal are 
bifurcated twice. The caudal fin, which constitutes a little less than the eighth of the total 
length, is posteriorly concave or sub-crescentic, and composed of twelve branched and two undi¬ 
vided rays, with a few rudiments on each side. The origin of the anal is nearly opposite the 
anterior margin of the second dorsal, with which it is even posteriorly. It is a lower fin, com¬ 
posed of twenty-one articulated rays and a small spine concealed in the skin at its anterior 
margin. Most of the rays are bifurcated, and the interradial membrane emarginated through¬ 
out. The ventrals are well developed, composed of five branched rays and a rather strong 
spine, though covered by the integuments. Their insertion takes place posteriorly to a vertical 
line passing immediately behind the base of the pectorals. Their posterior extremity does not 
extend as far as the tips of the latter fins, and leaves the vent far off. The insertion of the 
pectorals is quite oblique and reaches the inferior surface of the thorax ; they are very large 
broad, and long, composed of seventeen articulated and branched rays, the inferior ones stouter 
and shorter, with their interradial membrane emarginated. 
Br. VI—VI; D XXIV, 23; A I, 21; C 2, 1, 6, 6, 1, 2; V I, 5 ; P 17. 
The vent is placed considerably in advance of the anterior margin of the anal, and provided 
posteriorly with a fleshy, sub-conical appendage. 
