30 ZOOLOGY. 
length about nine times, or a little over. The greatest thickness stands, in regard to the 
length, as one to six or two to thirteen. The dorsal outline is more convex than in Percichthys 
chilensis, and mayhap also the belly, which contributes not in a small degree to give to this fish 
that more contracted appearance already alluded to above. The head is sub-conical, and par- 
ticipates in the short aspect of the body. Its upper surface continues, towards the tip of the 
snout, the declivity of the nape with scarcely any inflexion upon either the occiput or the ocular 
region. The snout itself is blunt and rounded, slightly overlapping the lower jaw when the 
mouth is shut. The upper arcade of the mouth is but little protractile, and, when in the latter 
state, causes the maxillaries to move more downwards than forwards. There are minute card- 
like teeth on both the upper and lower jaws, and closely set together. Velvet-like teeth may be 
observed on the front of the vomer, disposed upon a smal] triangle. The palatines exhibit a 
few rudimentary teeth upon their anterior extremity in contact with the vomer. The palate is 
otherwise smooth. The pharyngobranchials are large, elongated, and convex, and closely set 
with prickly teeth; the inferior pharyngobranchials are smaller, subtriangular, and slightly 
concave, likewise set with similar teeth. The tongue is smooth, flattened, tapering anteriorly. 
The mouth is moderate, the posterior extremity of the upper maxillary reaching a vertical 
which would pass in advance of the orbit only. The eye is subcircular, and well developed; its 
horizontal diameter being contained a little over four times in the length of the side of the head. 
The anterior suborbital is broadly developed, overlapping considerably the upper jaw. Its ex- 
ternal edge is minutely crenated. The serratures of the ascending branch of the preopercle 
are rather more developed than in P. chilensis, though the spines on the lower branch are pro- 
portionally of the same size. The opercular apparatus, as a whole, is constructed upon the 
same pattern in both P. chilensis and P. melanops. The inferior margin of the sub and inter- , 
opercle are similarly crenated, and a flattened spine may be seen across the middle of the oper- 
cle, extending its point beyond the edge of that bone, mayhap a little more acute and more 
conspicuous in P. melanops than in P, chilensis, The suprascapular is likewise cremated, and 
the coracoid expansion above the base of pectoral fins, wanting, however, the minute spines ob- 
served in P. chilensis. The branchiostegals, six in number, are flattened and curved. The 
gill openings communicate together under the throat, being shaped exactly as in P. chilensis. 
The distance between the tip of the snout and the origin of the first dorsal is a little greater 
than the base of both dorsals. The general structure of these fins is the same as in P. chilensis, 
with the exception that the third spine is the longest instead of the fourth. The membrane 
between the spines is deeply emarginated. Eight rays constitute, properly speaking, the ante- 
rior fin; two are intermediate between the eighth and the eleventh, which is situated at the 
anterior margin of the second or posterior fin. The central rays of the latter bifurcate also 
twice, and their tips extend evenly with those of the anal. The anal is preceded by three spines, 
and its soft rays are bifurcated in the same manner as those of the second dorsal. The poste- 
rior margin of the caudal is subemarginated with its central rays thrice bifurcated; it consti- 
tutes a little less than the sixth of the entire length of the fish. The origin of the ventrals cor- 
responds to a vertical line which would pass immediately behind the base of the pectorals. They 
are broad and rounded exteriorly ; their central rays being bifurcated three times, with the an- 
terior spine longer than in P. chilensis. The pectorals are rather short, and broad when ex- 
panded; their tips do not extend as far backwards as those of the ventrals; the rays are slender 
and bifurcate twice. 
Bro Vi Dox. 10: All 55 C6. 8 1.1 bs Vb: P15. 
The scales are of medium development, and very minutely, if at all, crenated upon their pos- 
terior margin, which is irregularly rounded. Their anterior margin is straight, and the upper 
and lower edges linear and parallel, the scales being much longer than broad. There. are ten 
distinct rows between the lateral line and the anterior margin of the first dorsal, besides some 
few irregularly disposed near the base of that fin; twenty rows and more may be counted 
