FISHES OF HAWAIIAN ISLANDS. 
71 
Genus 36. ARGYROPELECUS Cocco. 
Body much elevated and compressed, passing abruptly into the short tail; no scales, the skin 
covered with silvery pigment; series of luminous spots along the lower side of head, body, and tail; 
head large, compressed and elevated, the bones thin but ossified; cleft of mouth wide, vertical, the 
lower jaw prominent; margin of upper jaw formed by the maxillary and premaxillary, both of which 
have a sharp edge beset with minute teeth; lower jaw and palatine bones with a series of small curved 
teeth; eyes large, very close together, lateral but directed upward; angle of preopercle with a spine 
usually directed downward; pectorals well developed; ventrals very small; humeral arch and pubic 
bones prolonged into flat-pointed processes, which project in the median line of the belly; a series of 
imbricated scales from the humeral bone to the pubic spine, forming a ventral serrature; dorsal fin 
short, median, preceded by a serrated, osseous ridge, consisting of several neural spines prolonged 
beyond the muscles; adipose fin rudimentary; anal fin short; caudal forked; gill-opening very wide, 
the outer branchial arch extending forward to behind the symphysis of the lower jaw and beset with 
very long gillrakers; branchiostegals 9, the arch near lower jaw and parallel with it; pseudobranchise 
and air-bladder present; 4 pyloric coeea. Small pelagic fishes found in most seas, coming to the 
surface at night, descending into deep water by day. 
The single Hawaiian species of this genus is fully described in Section II. 
Argyropelecus Cocco, Giorn, Sci. Sicil., fasc. 77, 146, 1829 ( hemigymnus ). 
Pleurothyris Lowe, Fishes of Madeira, 64, 1861 ( olfersi ). 
Family XXII. CHAULIODONTID/E. 
Body more or less elongate, covered with thin caducous scales, or sometimes naked; photophores 
present; mouth large, the teeth irregular in size; maxillary entering margin; no pseudobranch ire ; 
interopercle rudimentary; gill-openings wide; dorsal and anal moderate or large. Deep-sea fishes of 
rather small size but voracious habits. Some 7 genera and about 20 species known. 
Genus 37. CYCLOTHONE Goode & Bean. 
Body elongated, somewhat compressed, apparently devoid of scales; lower parts with inconspicu- 
ous series of luminous spots, with the latter arranged approximately as in Gonosloma, lint usually much 
less conspicuous; head conical, compressed; cleft of mouth very wide, oblique, extending behind the 
eye; lower jaw strongly projecting; maxillary long and slender, sickle-shaped, somewhat dilated pos- 
teriorly, but covering only an inconsiderable portion of the cheek; upper jaw with a single series of 
needle-like teeth, some of which are enlarged; lower jaw with similar teeth, and in some species with 
a few canines in front; teeth on vomer sometimes in patches, sometimes reduced to a single pair of 
fangs; palatine and pterygoid teeth present or absent; eye moderate, not conspicuous; gill-opening 
very wide, the membranes free from isthmus; gillrakers numerous, long and slender; pseudobranchite 
none; no air-bladder; dorsal and anal moderate, opposite, the latter much the longer; adipose fin 
sometimes present. The 3 Hawaiian species of this genus are fully described in Section II. 
Cyclolhone Goode & Bean, Bull. Mus. Comp. Zool., x, No. 5, 221, 1883 (lusca). 
Sigmops Gill, Proc. U. S. Nat. Mus. 1883, 256 (stigmaticus) . 
Family XXIII. ASTRONESTHIDtE. 
Stomatoid fishes, with adipose dorsal present, and with scaleless body; dorsal fin inserted behind 
vent, but in front of anal. A single genus with few species; fishes of the deep sea. 
Genus 38. ASTRONESTHES Richardson. 
Body rather elongate, compressed, scaleless; head compressed; snout of moderate length; mouth 
wide; lower jaw prominent; teeth pointed, unequal; upper jaw with 4 long, curved canines, front of 
lower with 2; maxillai’y teeth fine, subequal; palatines with a single series of small pointed teeth, simi- 
lar to those on tongue; eye moderate, not longer than snout; throat with a long fleshy barbel; dorsal 
fin rather long, inserted entirely in front of anal behind ventrals; adipose fin present; caudal forked; 
