132 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



ACANTHURIDiE. 



122. Acanthurus chirurgus (Bloch). Tavg. 



Coniiiioii, tlie young- taken with the seine ah>ng the shore; the adult 

 with the hook in the channels. 



Adult olive-brown, more or less distinctly greenish ; middle of sides 

 paler; breast tinged with blue; sides with about twelve distinct 

 blackish vertical bars, rather narrower than the intersi)aces, most dis- 

 tinct over front of anal ; a bronze-olive stri])e along" base of dorsal ; 

 head olive, slightly tinged with blue on the])reorbitaI ; lips light l>luish; 

 edge of opeicle dusky ; four or live yellowish streaks extending across 

 eye, oblicjuely ui)ward and backward ; region at base of caudal si)ine 

 blue-black, the black surrounded by a sky-blue ring; a pale olive ring- 

 around base of caudal. 



Spinous dorsal with alternate strii)es running ui)wardand backward, 

 of dark blue and bronze-olive, the two colors of about equal width. 

 Soft dorsal with a bluish streak on the front side ol" each ray and a 

 bronze stripe behind it, the tin sometimes showing horizontal bluish 

 streaks; anal similarly marked; edge of dorsal and anal narrowly sky- 

 blue; caudal dark, tinged with blue; anal ami ventral similar. Pec- 

 toral blue above, its median region washed with olive. 



123. Acanthurus tractus Poey. 



Several young si)ecimens taken, apparently of this species. lu life, 

 olivaceous, with longitudinal reticulating lines of darker olive, very 

 close set ; stri[)es on tins nearly horizontal, distinct and i)arallel, similar 

 and continuous on both the spines and the solt rays ; caudal lin dull 

 yellow-olive, the pale ring at its base faint ; edge of opercle black. 

 The caudal lin in these is much more deeply lunate than in either youug 

 or adult of A. chirurgus, the depth of the emargiuatiou iu both species 

 increasing with age. 



124. Acanthurus coeruleus (Bloch)- J>lue Tang. 



{Acanthurus brevia Poey). 



A single young specimen apparently corresponding to the Acanthu- 

 rus brevis of Poey, obtained. " Blue Tangs'^'' are occasionally taken, 

 according to the fishermen. 



Color light olive, with narrow, horizontal, wavy streaks of darker olive, 

 slightly tinged with bronze, these lather conspicuous and very numer- 

 ous, lielly livid bluish ; a whitish ring at base of caudal ; edge of op- 

 ercle blackish ; a faint blue stripe and some orange before eye. Both 

 dorsals pale bright orange, with six stripes of light slaty-blue, contin- 

 uous and horizontal on both parts of the fin ; edge of dorsal light blue, 

 its base orange; caudal dull yellow with a whitish edge. Anal marked 

 like dorsal, but the bluish darker and the i)ale color dull yellowish- 

 brown, the edge of the fin dusky. Ventrals violet, blackish at tip. 

 Pectoral light yellow ; caudal si)ine yellow. 



This differs from adult specimens from Cuba only in the ground color, 



