44 ZOOLOGY. 
Descr. The head constitutes about one fourth of the entire length, and is in direct continuity 
with the trunk, being slightly declive from the occipital region towards the tip of the snout, 
which has the shape of a flattened cone. The anterior margin of the anterior nostril opening 
is nearly equidistant between the tip of snout and the anterior rim of the orbit; the posterior 
nostril opening is situated immediately behind the former; both being rather small and of the 
same development. The eye is large and subcircular, its upper rim approximating the line of 
the profile of the head. Its horizontal diameter is contained a little over four times in the 
length of the side of the head, and once between the tip of the snout and the anterior rim of 
the pupil. The extremity of the lower jaw does not extend beyond a vertical line, which would 
pass immediately in advance of the anterior nostril. The posterior extremity of the upper 
maxillary reaches the extremity of the preopercular carina: not the posterior limb of that bone. 
The intermaxillaries, the maxillaries upon the whole extent of their margin, and the dentaries, 
are minutely crenated, not to say serrated, or toothed. The middle lingual carina is quite 
conspicuous, and obsoletely crenated also. The posterior edge of the opercular apparatus is 
convex, and subelliptically rounded. Its component pieces are smooth, except the upper por- 
tion of the opercle, which exhibits a few minute carina. The preopercle sends off a thin ex- 
pansion of its limb over the junction of the opercle, subopercle, and interopercle. The gill 
openings are broadly open under the head, extending forwards almost opposite to the anterior 
rim of the pupil. 
The body is slender, subfusiform, and compressed ; deepest anteriorly, and gradually tapering 
posteriorly in depth and width. The greatest depth, taken across the base of the pectoral fins, 
is contained over six times and a half in the total length; whilst the least depth, near the base 
of the caudal fin, is scarcely half the latter. The greatest thickness, upon the thoracic region, 
is a little more considerable than the least depth. The peduncle of the tail is flattened, and 
wedge-shaped towards the base of the caudal fin. The back is uniformly rounded or convex, 
and the ventral region narrow. The anterior margin of the dorsal fin is equi-distant between 
the tip of the snout and the base of the caudal; its anterior margin is equal in height to its 
base, and its posterior margin is about one fourth of the anterior margin. Its upper margin is 
slightly subconcave. The origin of the anal is opposite the tips of the posterior rays of the 
dorsal. Its base is one fourth longer than that of the dorsal, and its anterior margin about the 
three fourths of its base. It is concave upon its external margin, and rapidly decreasing in 
depth beyond the anterior third of its length. The rays of the dorsal and anal subdivide but 
once upon the posterior third of their length. The caudal is slender and deeply forked, con- 
stituting a little less than one seventh of the total length; its central rays are subdivided three 
times with obsolete indications upon their tip of a subdivision of the fourth degree. The ven- 
trals are rather short, broad exteriorly when expanded, and rounded or convex upon their 
margin; their central rays subdividing twice. Their origin is situated in advance of the ante- 
rior margin of dorsal, and their tips extend slightly beyond the middle of the base of the same 
fin. The pectorals are rather slender, and attached to the inferior part of the thoracic region ; 
their external margin is much longer than the internal, and moderately broad when expanded. 
Their central rays bifurcate twice upon their length; the anterior one being simple, as well as 
that of the ventrals. 
Br. TX; Dd6s Ais CS. EO Sials oa. vers bk. 
The anterior two rays of the dorsal and anal fins are simple, the first being but little de- 
veloped. 
The scales are very large, much deeper than long, irregularly rounded, convex posteriorly, 
and undulated anteriorly. Five longitudinal rows may be counted immediately above the pos- 
terior extremity of the anal fin, and perhaps six or seven rows upon the line of greatest depth 
of the body. 
The lateral line is not discernible. 
