FISHES OF HAWAIIAN ISLANDS. 
593 
Diameter of eye longer than snout, but shorter than interorbital width ; maxillary very long and 
narrow, extending far behind middle of head, its posterior portion not at all widened; both premaxil- 
lary and mandible armed with broad hands of fine depressible teeth, which extend over the outer as 
well as the inner margins of the jaws; two small separate vomerine patches, one on each side of 
median line, a long narrow palatine band, and a longer broader pterygoid band, parallel to palatine 
hand and extending farther backward; gill-rakers long and slender, 5-f-13 in number, toothed along 
their inner margins, the longest two-thirds the diameter of orbit. 
Insertion of first dorsal and the outer ventral rays in the same vertical; base of last dorsal ray 
vertically above vent; front of adipose fin over last anal ray; pectoral reaching fourth thoracic photo- 
phore, the inner ventral rays barely reaching vent. 
Scales caducous, all having fallen in the type. In one of the cotypes a few scales remain, which 
show that those of the lateral line are not enlarged, and that all have entire edges. 
As in other species of Diaphus, the fourth thoracic photophore is elevated laterally to a point on a 
level with the base of the pectoral fin; the third ventral photophore is on the same level, the second 
ventral forming with the first and third an oblique line extending upward and backward; supra- 
ventral high, slightly nearer lateral line than base of ventral; supra-anals 3 in number, forming 
an oblique line from just before vent to lateral line, the upper supra-anal immediately below the 
lateral line, widely separated from second supra-anal; first anal remote from anal base, on a line join- 
ing second anal with upper supra-anal; second, third, and fourth anals lie near base of anal fin, the 
fifth and sixth diverging in a curved line which includes the single posterolateral; the latter is sepa- 
rated from the lateral line by one-fourth its distance from the anal base; five posterior anals in a 
straight line along anterior half of caudal peduncle; caudals 4' in number, equidistant in a curve at base 
of lower caudal lobe, the upper spot well below middle of caudal base; pectorals 3 in number, the 
upper at tip of opercular flap, the lower intermediate between the first thoracic and the spot at base 
of pectoral; a narrow luminous (golden) streak on upper orbital rim, and one along anterior half of 
lower margin, both of them conspicuously margined with black; no luminous patches on tail; a semi- 
circular white glandular body between pectoral base and upper pectoral spot, similar to the one occu- 
pying the same position in D. theta. The division of the photophores can be made out only where 
they still lie protected beneath the scales. 
General color dusky, the bases of all the fins except the pectoral black; anterior dorsal and anal 
fin blackish; opercle black, cheek silvery, snout whitish; interorbital space black, except a small 
whitish median area; a broad black subocular bar, from which a narrow black ring encircles anterior 
half of orbit; gular membrane black, its anterior portion violet; a black bar near tip of mandible, and 
one across mandible below eye; lining of buccal and gill-cavities and the peritoneum black. 
The condition of all the specimens indicated that they entered the dredge near the bottom. They 
were taken at the following stations: No. 3920, off south coast of Oahu, 265 to 280 fathoms; 4015, 
vicinity of Kauai, 318 to 362 fathoms; 4106, Kaiwi Channel, 335 to 350 fathoms. 
This species resembles D. engraulis Gunther, from the Philippines, but differs in the darker colora- 
tion, the different shape of the circumocular luminous patches, and the higher position of the upper 
supra-anal and the posterolateral photophores. 
Centrobranchus Fowler. 
Allied to Rhinoscopelus, but without lateral line and with the gill-rakers obsolescent. The slender 
snout protrudes far beyond the premaxi llaries, and is hollowed out on each side to form a conspicuous 
nasal cavity, which is entirely roofed over by the expanded preorbitals; these are strongly convex 
outwards and cover the entire lateral portions of the snout, joining superiorly and anteriorly the mid- 
rostral ridge, and in contact below with the premaxillaries; their posterior margin is notched to give 
passage to the nasal openings; gill-rakers reduced to a few rudiments near angle of arch; photophores 
arranged as in Rhinoscopelus and Myctophum, all those of the lower series forming parallel rows, none of 
them elevated on the sides, and the caudal photophores but 2 in number. 
Centrobranchus Fowler, Proc. Ac. Nat. Sci. Phila., 1903 (Jan. 13, 1904), 754 ( chcerocephalus ). 
