FISHES OF HAWAIIAN ISLANDS. 
635 
Body elongate, little compressed, width two-thirds depth; upper profile of head rising in a gentle 
unbroken curve from snout to dorsal fin; head without pits or depressions; interorbital space wide, 
flat or very gently concave; a series of very strong, compressed, backwardly hooked spines along lateral 
profile of head, 1 on preorbital, 2 on suborbital stay, and 1 on preopercular margin; a smaller cusp at 
anterior base of each larger one, that at base of preopercular spine larger than the others; in front of 
the preorbital and the anterior suborbital spines several smaller spinelets; beneath the preorbital spine a 
second series of short backwardly hooked spines overlapping maxillary; opercular margin with 2 spines, 
the lower terminating a knife-like ridge which bears 2 smaller spines; supraorbital rim not elevated, 
bearing a row of strong spines directed outward and backward; within these a pair of curved, diverging, 
finely serrulate ridges; occipital ridges very short, with diverging spines; 2 or 3 paroccipital spines; a 
strong suprascapular spine; mouth very small, horizontal; mandible included; maxillary narrow, 
scarcely reaching vertical from front of pupil; finely villiform teeth in jaws, vomer, and palatines, the 
palatine band very narrow, the outer series in premaxillaries a little enlarged; branchiostegals 7, mem- 
branes distinct and free; pseudobranchise large; gill-1 ami nre much reduced, the posterior filaments of 
fourth arch rudimentary; slit behind fourth arch evident; gill-rakers short, unarmed, less than one- 
third diameter of pupil, 11 or 12 on horizontal limb of first arch. 
Spinous dorsal low, with evenly rounded contour, the fourth spine highest, the tenth very short, 
its membrane not joined to the eleventh, which is much longer; twelfth' spine as long as ninth and but 
little shorter than soft rays; first anal spine about as long as third, much shorter than second; base of 
Fig. 248 . — Plectrogenium nanum Gilbert, new species. Type. 
anal equal to that of second dorsal, the 2 fins exactly opposite; upper pectoral rays slender, all but 
the upper 2 forked, about 8 of the lower rays simple and a little thickened, some of them produced, 
longer than the rays above and below them, but not so long as the longest pectoral rays, which reach 
to or a little beyond front of anal; third ventral ray longest, reaching first anal spine; caudal slightly 
emarginate. 
Scales large, strongly ctenoid, those on head and pectoral fin much reduced in size; lateral line of 
normal type, each scale bearing a tube which opens in a pore near margin of scale; no cutaneous canal 
overlying the scales, as in Setarches; only mandibles, lips, and gill-membranes scaleless. 
Color in life almost uniform rose-red; a dusky streak on membrane behind distal half of each 
dorsal spine, and a dusky blotch on middle of soft dorsal, these colors more intense in the young, 
where a faint dusky bar may often be detected beneath each dorsal fin, and a narrow streak on middle 
of caudal peduncle; mouth, branchial and abdominal cavities whitish. 
Bones of head firm and not heavily channeled, the species not evidently adapted for life at 
considerable depths. Fifteen specimens -were secured. 
Specimens were taken at the following stations: Nos. 3952, vicinity of Laysan, 347 to 351 fathoms; 
4079, off the north coast of Maui, 143 to 178 fathoms; 4080, off the north coast of Maui, 178 to 202 
fathoms; 4081, off the north coast of Maui, 202 to 220 fathoms; 4082, off the north coast of Maui, 220 
to 238 fathoms; 4132, vicinity of Kauai, 257 to 312 fathoms. 
