206 



BULLETIN 10 0, UNITED STATES NATIONAL MUSEUM 



D. IX, 19 or 20, ninth spine 1^ to 2}4 in head, first ray 1^ to 

 2^; A. Ill, 19, third spine 2^ to 23^, first ray ly^ to 2^; caudal 

 slightly emarginate behind, points little exserted, truncate in young, 

 l}4 to 13^; least depth of caudal peduncle 2J^ to 3; pectoral 1^; 

 ventral 1 J^ to 2, spines robust; caudal spine 3}^ to 4. 



Gray brown generally, variably more bluish gray in some examples, 

 especially about head and costal region. Broad, blackish-brown 

 band strongly contrasted, like all rest of similar dark color of back; 

 band extends up above suprascapular region or along upper edge of 

 back, gradually broadening until reaching front of caudal peduncle; 

 a forward extension continued along median axis of tail from caudal 



Fig. 10.— Variation of color markings of Paracanthurus theuthis (LAcftpfcDE) 



spine till nearly above pectoral base; with age this band slopes up 

 to dark dorsal band with which it unites just behind suprascapular 

 region; posteriorly dark area of back extends above and below as 

 strongly contrasted border both along caudal peduncle and caudal 

 fin, pale intervening cuneate area resulting yellowish buff. Iris 

 dusky. Bases of dorsals and anals broadly grayish or light bluish 

 with tinge of light brown, margins of fins broadly blackish. Pectoral 

 grayish or blue-gray over greater basal half or more, dusky above, 

 and hind margin broadly pale yellowish buff; young with uniform 

 pale pectoral. Ventral pale hind edge little brownish. 

 Mauritius to the East Indies, Philippines, Melanesia. 



14269, 14620. Doc Can Island. January 7, 1910. Length 74 to 153 mm. 

 A1640. Philippines. Length 217 mm. 



