72 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 
of Goto Islands, Eastern Sea. In 139 fathoms. August 10, 1906. 
Length 39 mm. 
(gracile, slender.) 
Family OPLICHTHYIDAE 
ACANTHOPLICHTHYS, new genus 
Type.—Acanthoplichthys pectoralis, new species. 
Body well elongated and depressed, depth less than half of great- 
est width. Head large, broadly depressed. Snout broad, long, 
broadly obtuse in front. Eye small, supralateral, median in length 
of head and close to but not invading upper profile. Maxillary 
reaches below front of eye. Mouth broad, terminal, closed lower 
jaw slightly shorter or included. Teeth, if present, very minute, not 
evident, and jaws and palate smooth. Interorbital greatly wider than 
eye. Gill opening very large, extends forward below eye. Gill 
rakers small low tubercles, rather few. Skin largely smooth, scale- 
less. Ridges of head above and edges of suborbital stay spinescent, 
though all spines on head small and little differentiated. Row of 
rather large spines all along lateral line. Two dorsals, well sepa- 
rated, first small and lower than second. Anal like second dorsal, op- 
posite, its rays all little longer. Caudal small, rounded convexly 
behind. Caudal peduncle small, slender, free. Pectoral greatly 
elongated, reaches halfway to hind edge of caudal and lower 3 rays 
detached. Ventral short, not reaching anal. 
Approaches Rhinhoplichthys Fowler in the large smooth elongate 
areas on the head before the eyes and the broad interorbital width. It 
differs at once in the greatly extended pectorals. 
(axavOa, spine+Hoplichthys, with reference to its spinescent 
armature.) 
ACANTHOPLICHTHYS PECTORALIS, new species 
FIGURE 15 
Depth 834; head 234, width 114. Snout 224 in head; eye 8, 314 in 
snout, 124 in bony interorbital width; maxillary reaches front eye 
edge, length 224 in head; mouth width 244, lower jaw shorter than 
upper and included when closed; teeth not made out, jaws and 
palate smooth; bony interorbital width 5 in head, low, level. Gill 
rakers 3+5, short, low tuberclelike knobs, greatly lower than gill 
filaments. 
Frontal ridges, also parietal, occipital and postocular with rows of 
small spines or spinules. Two divergent spinescent ridges on opercle. 
Suborbital stay with spinescent edges and two long spines at angle 
