PISHES OF THE PHHiIPPINE AND ADJACENT SEAS 187 



Holacanthiis rhomboides Gilchrist and Thompson, Ann. South Afric. 

 Mus., vol. 6, 1908, p. 161. Natal. 



Depth 1% to IM; head 2^ to 3^, width 1% to 2. Snout 2J4 to 

 3 in head from snout tip; eye S}i to 3j^, 1 to 13^^ in snout, greater 

 than interorbital; maxillary to front nostril in vertical, S}4 to S}/2 in 

 head; interorbital 3% to 4>^, broadly convex; preopercle spine along 

 upper edge 3f4 to 6^, much shorter in very young. Gill rakers 

 6 + 12, lanceolate, short, }4 of gill filaments, which 13^ in eye. 



Scales 65 to 70 between gill opening and caudal base; 12 or 13 

 scales above lateral hne, 34 or 35 below. Scales with 3 to 6 basal 

 radiating striae; apical denticles 21 to 34, each with rather slender, 

 moderately long rootlet and 3 or 4 series transversely of small basal 

 spinelets; circuli fine. 



D. XIII, 20, I to 21, I, last spine 1}4 to l}4 in total head length; 

 seventh ray 27-5 to 2^ in combined head and body; A. Ill, 18, i or 

 19, I, third spine 1J4 to 2 in total head length, sixth ray 1 to l}/s> 

 least depth of caudal peduncle 23^3 to 2%; pectoral m to l^-g; ven- 

 tral 2^ to 2]4. 



Largely blackish-brown, with age becoming little paler or more 

 brownish on sides medially and abdomen. Eighteen transverse or 

 vertically-placed whitish lines, variably arched or with upper and 

 lower portions inclined backwards, those on tail posteriorly usually 

 greatly curved; usually first, second, fourth, sixth, eighth, tenth, 

 twelfth, fourteenth, sixteenth, and eighteenth much wider. In young 

 these wider bands the only ones present, the intervening ones gradu- 

 ally appearing with age ; the alternating lines always conspicuously 

 narrower than the fundamentals; also intervening brown areas on 

 middle of trunk and front of tail with many close-set, small, dusky 

 or blackish spots in adults. Light lines all extend to vertical fins, 

 variably converging more or less as broken bars and spots on soft 

 dorsal and anal. Caudal dusk}^ brown with 2 whitish transverse 

 basal lines, variously broken as [-shaped. Borders of soft vertical 

 fins all narrowly bluish. Pectoral brow^nish. Ventral dusky, front 

 border blue and several blue lines. Young with outer half of 

 caudal uniformly pale. Iris dusky. 



Zanzibar, East Indies, Melanesia, Polynesia. A very handsome 

 species though the light lines variable. In bne of our adult examples 

 the fourteenth loops over before the caudal peduncle and joins with 

 the sixteenth on the left side of the body. In a young example the 

 posterior whitish lines are nearly straight and parallel on the tail, 

 though oblique on the vertical fins. As Ogilb}^ says it is a small 

 species though our largest example is considerably more than his, as 

 120 mm. compared with 165 mm. 



19469. Batan Island. July 22, 1909. Length 45 mm. 



8507. Entrance Puerta Princesa Bay. April 5, 1909. Length 165 mm. 



