502 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 
obsolete distally; the bases of the plates are bounded on each side by 
one or two scales. The infraorbital ridge is covered by two series of 
scales behind the middle of orbit. The ridges of the head are cov- 
ered by rather strong scales, mostly close-set with spinules; the 
occipital and postorbital ridges, together with the posterior half of 
the supraorbital ridge, are covered by strong scales bearing a few 
spinous keels directed backward; the scales on the median rostral 
ridge are oval or subquadrate in outline, and are armed by several 
series of spinules radiating in all directions from near the center 
of each scale. The occipital scute is provided with a strong median 
keel, and with two (one to several) carinae on each side; the 
median scute is preceded on each side by a weaker one; a similar 
scute is located just above the origin of the lateral line. The three 
to five rows of scales covering the region between the occipital ridges 
are armed by several high, divergent, serrated ridges. The supra- 
narial and medial rostral ridge scales are each bounded by scales in 
single series, separated from each other by a narrow groove; this 
groove widens forward and merges into a rather wide anterolateral 
groove, which, though parallel with the infraorbital ridge, is sepa- 
rated from it by a series of prickly scales; this naked area in the 
young occupies most of the anterolateral region of the snout, but in 
the largest specimens is reduced to a narrow groove. Below the orbit 
and in areas extending backward thence to the preopercular ridge, 
and forward to the nasal fossa, the scales are reduced in size and 
spination; the scales between the occipital and infraorbital ridges 
are otherwise similar to those of the body; the median of the three 
main series of scales between the occipital and postorbital ridges is 
shghtly enlarged. The nasal fossa and the underside of the head are 
completely naked in all specimens. 
Base of first dorsal, 1.9 (1.3 to 2.2) in interdorsal space, about 
half postorbital length of the head; the second dorsal fin is weak 
anteriorly. The outer ventral ray is filamentous; it enters 2.85 (2.4 
to 3.2) times into the head; the second ventral ray extends to the 
anus. The anal fin is inserted a little in advance of the second 
dorsal. 
Color in alcohol, light brown, with silvery reflections on the lower 
sides; the head is hghter in general, but dusky on the opercles. 
Other specimens are very pale brownish on the trunk and tail and 
whitish on the head. The second dorsal fin is ight; the filament 
of the outer ventral ray is whitish; the other fins are dusky, quite 
light in the more faintly colored specimens. The lning of the 
buceal cavity is dark, becoming lighter toward the gape in some 
specimens; that of the branchial cavity is blackish, with an abrupt 
whitish margin along the opercular and branchiostegal membranes; 
the parietal peritoneum is purplish or brownish black. 
