af 
HOPLOSTETHUS PACIFICUS. o7 
Depth of head equal to its length, which is twice its width; forehead very 
convex, a prominent median ridge above the nostrils. Snout short, hardly 
as long as the eye, blunt, steep and strongly curved above the mouth, most 
prominent forward in the angle at the mandibular symphysis. Nostrils 
small, immediately in front of the eye; hinder larger, vertically oblong; 
anterior small, round, lower than the posterior. Eye large, prominent, 
one fourth as long as the head, less than the width of the interorbi- 
tal space, considerably below the level of the top of the head. Skull 
deeply excavated for the lateral system; the channels of the system, 
between the bridges protecting the disks, are covered by very thin and 
delicate membrane in which there are numerous minute pores. Mouth 
large, oblique; lower jaw longer; maxillary visible backward of the nostrils, 
broadening till nearly as wide as the eye at the end, curving downward in 
the middle of the upper edge, not entering the mouth border, with a supple- 
mental bone as long as the orbit. Teeth in villiform bands on jaws and 
palatines, absent from the vomer. <A prominent angle at the mandibular 
symphysis, another below the articulary; a spine-like prominence behind the 
scapulary, and another at the angle of the preopercle. All exposed por- 
tions of the skull are roughened; the bridges crossing the canals of the lat- 
eral system are comparatively strong, though the bony structure generally 
is fragile. Edges of gill covers thin and membranous; operculum twice as 
high as long. Gills four; lamella of medium length; rakers six plus fifteen, 
acicular, shorter than the eye. Pseudobranchiz moderately developed. 
Suprabranchial gland of medium size, vertically oblong or subelliptical, 
with a groove in the middle, resembling that of Lamprogrammus but not 
quite so annular. The position of this gland and the arrangement of the 
disks of the lateral system on the head, with several of the anterior disks 
of the body, are shown on Plate LXXI., fig. 4. Scales irregular, somewhat 
convex, more or less rough with ridges or crowded small spines or granula- 
tions, in about fifty-eight transverse series; scales of the lateral line twenty- 
eight, much larger, prominently convex, forming a strong ridge along the 
side. The scales of this line belong to alternate ones of the transverse 
series, but each scale in the line is so large as to crowd out the scales of the 
intermediate rows, thus forming a continuous row of large scales. In the 
median abdominal series there are about eighteen sharp scales, varying from 
fifteen to nineteen. 
Dorsal origin midway from anterior nostril to end of the base of the 
