FAMILY BALISTIDAE — WOODS 115 



mouth, just behind Ups; broad bhie line extending from anterior 

 portion of dark interorbital patch, anterior to eye, downward, curving 

 posteriorly toward ventral part of pectoral base; margins of black 

 triangular caudal peduncle patch bright yellow; upper margin of 

 posterior half of black diagonal body band and line extending to 

 posterior dorsal base bright golden yellow; pectoral fin with bright 

 red transverse band just distal to black base. 



RHINECANTHUS ACULEATUS (Linnaeus) 



Plate 140,B 



Balistes aculeatus Linnaeus, Systema naturae, ed. 10, p. 328, 1758 (type locality, 

 India) . 



SPECIMENS STUDIED 

 Bikini Atoll: 10 stations, 18 specimens, 106 to 175 mm. in standard length. 

 Eniwetok Atoll: 1 specimen, 145 mm. 

 Rongerik Atoll: 2 stations, 5 specimens, 25 to IGl mm. 

 Guam: 10 lots, 32 specimens, 29 to 160 mm. 

 Rota Island: 2 lots, 2 specimens, 136 and 155 mm. 



Description. — Dorsal fin rays III-ii,23 or 24; anal rays i,21 or 22; 

 pectoral rays i,12 or 13; branched caudal rays 5+5; gill rakers on 

 first arch 21 to 25 long, slender, pointed about 2.7 to 3.0 in eye; scale 

 rows 41 or 42; teeth in upper jaw 8, lower jaw 8. 



Depth of body 1.7 to 2.4; length of head 2.2 to 2.5; both in stand- 

 ard length. Snout 1.2 to 1.7; diameter of eye 3.1 to 7.5; least depth 

 of caudal peduncle 4.3 to 5.3; length of pectoral fin 2.2 to 3.3; length 

 of longest soft dorsal ray 2.7 to 3.3; length of longest anal ray 2.7 to 

 3.7; length of middle caudal fin rays 1.5 to 2.4; interorbital width 

 3.3 to 4.7; all in length of head. Angle of snout profile 28 to 37 

 degrees, snout profile almost straight, sometimes slightly concave or 

 convex. 



Teeth large, white, deeply notched; no deep groove before eye 

 below nostril; interorbital smoothly convex; third dorsal spine not 

 projecting above rim of groove; caudal peduncle armed with 3 rows 

 of spines, 2 upper rows with 10 to 12 spines each of about equal 

 length, lower row with 3 to 5 spines, a third to half length of upper; 

 caudal peduncle constricted; caudal fin rounded in young, subtruncate 

 in adults. 



Color in alcohol. — Ground color of upper parts light greyish brown, 

 of under parts pale yellowish white; lips light brown or yellowish, a 

 faint bluish white line around mouth just behind lips (usually absent 

 on chin) ; interorbital area dark grey with 2 to 4 darker lines crossing 

 interorbital space; narrow white or greyish line running from anterior 

 part of eye downward and curving in to lower edge of pectoral inser- 

 tion; a dark band, slightly narrower than eye, sometimes white 



