FISHES OF THE PHOENIX AND SAMOAN ISLANDS 243 



anus 50.5; longest spine (second) of dorsal fin 18.7; longest (fifth 

 or sixth) soft ray of dorsal fin 15.3; longest (ninth) soft ray of 

 anal fin 17.2 ; longest ray of caudal fin 26.2 ; longest ray of pectoral 

 fin 22.7; longest ray of pelvic fin 24.8; length of first dorsal spine 

 15.3; length of spine at front of soft dorsal fin 13.1. 



Dorsal fin rays VI-1, 10 ; anal I, 10 ; pectoral 18 ; pelvic I, 5 ; number 

 of scale rows from gill opening to base of caudal fin 28; scales along 

 midline of back in front of dorssal fin 10; number of scales in the 

 transverse row from front of dorsal to anal fin 8. 



Color in alcohol, pale with fine pigment spots along midaxis of 

 body and an additional one basally on caudal fin rays; upper sides 



Figure 21. — Oplopomus diacanthus, new species: Holotype (U. S. N. M. No. 116116), 

 34.3 mm. in standard length. 



with scattered patches of pigment cells; gill membranes white; pec- 

 torals white; body with several areas of silvery white, rather large 

 ventrally but small dorsally; below eye an oblique color bar and 

 another across opercle; three tiny patches of pigment in line from 

 front of eye to tip of snout; interorbital with a few pigment cells. 

 Gill membranes broadly joined to isthmus, the gill opening not 

 restricted to in front of the base of pectoral fin ; cheeks and opercles 

 naked; midline of back in front of dorsal and sides of nape scaled 

 to eyes; breast scaly; abdomen scaled; base of pectorals scaled; 

 scales ctenoid ; mouth somewhat oblique, the maxillaries reaching to 

 below front of eye; tongue truncate; teeth in upper and lower jaws 

 conical and arranged more or less in a villiform band with the outer 

 ones on the lower jaw rather strong and hooked forward ; no cutaneous 

 flaps on shoulder girdle; interorbital space very narrow; anterior 

 nostril tubular; basal membrane well developed with the usual lobes 

 then a notch just before it joins the pelvic rays; pelvic fins attached 

 along midline to each other but not joined by membrane to the 

 abdomen ; caudal fin rounded ; jaws of almost equal length, the lower 

 a trifle longer. 



