158 BULLETIN 180, UNITED STATES NATIONAL MUSEUM 



to 28 ; pectoral 1, 15 ; teeth 12 to 14 + about 14 ; gill rakers 



about 5 + 11 Acanthunis lineatus (Linnaeus) 



91). Head and trunk not marked with definite color pattern of 

 longitudinal lines or bands. 

 lOa. Gi'ouud color sepia-brown, posterior half of body including 

 dorsal and anal fins spotted with white ; caudal fin not 

 spotted with white, usually three (rarely four) vertical 

 pale bars, first from occiput just behind eye to opercle, 

 second from under spinous dorsal just behind pectoral 

 base to belly, third (sometimes vei'y faint) from front 

 of soft dorsal to front of soft anal ; sometimes a trace 

 of a fourth from in front of spine on caudal peduncle to 

 a point about two-thirds along base of anal ; region below 

 pectorals and breast pale ; basal two-thirds of caudal fin 

 pale, the distal third blackish or brownish, dorsal rays 

 IX, 27 or 28; anal III, 24 or 25; pectorals I, 15; teeth 

 about 10 + 12 ; gill rakers about 6 + 16. 



Acanthurus guttatus Bloch 

 10&. Posterior part of trunk and of dorsal and anal fins without 

 traces of numerous pale spots on a dark background of 

 color, 

 llo. Base of caudal fin and including posterior part of caudal 

 peduncle with a transverse pale band that extends 

 posteriorly along dorsal and ventral edge of caudal 

 fin base a distance equal to width of band at axis of 

 peduncle, rest of caudal fin dusky, very near edge of 

 that fin with a white line; ground color uniform 

 grayish or dusky ; upper lip blackish ; outer rays of 

 pelvics dusky or blackish ; dorsal and anal more black- 

 ish than body, base of dorsal fin with a dusky line; no 

 white transverse band behind eye and no black spots 

 at bases of last rays of dorsal and anal fins, as in the 

 type of Teuthis Icucopareius, and tip of pectoral 

 rounded instead of pointed as in latter species ; dorsal 

 rays about IX, 26 ; anal III, 24 ; pectoral I, 16 ; teeth 

 about 16+18; gill rakers about 5-^-13. 



Acanthurus umbra (Jenkins) 



11&. No transverse pale band across base of caudal fin or on 



caudal peduncle. 



12a. Base of pectoral flu pale, also a pale horizontal band 



through eye; trunk with many fine, longitudinal, 



somewhat obscure, slaty lines; pale slaty-blue line 



along dorsal base ; caudal slaty with blue spots ; in 



alcohol dorsal and anal fins often show longitudinal 



lines too; dorsal rays IX, 25 to 27; anal III, 24 to 



26; teeth 16 to 20+16 to 20; gill rakers 5+15 to 18. 



(After Giinther and after Fowler.) 



Acanthurus bariene Lesson 

 12&. Base of pectoral blackish and no pale band through 

 eye; ground color blackish or grayish, often with 

 numerous obscure dark purplish or dark bluish lon- 

 gitudinal lines, more obvious on paler specimens; 

 vertical fins blacker than body, caudal fin with pale 

 or white line posteriorly, wider in young and more 



