139 



head and chest. Lancet-shaped spine with a posterior process. 

 Least depth of free portion of the tail |- of length of head. Colour 

 blue, head dark brown or black, chest white, as is also a ring on 

 lower part of mouth, ascending to its angle. A broad bluish band 

 passes down the shoulder to the axilla, which last has a triangular 

 brown patch. A narrow cresceiitic black band across base of 

 caudal, continued along the upper and lower edges of the fin, a 

 second wide one along the last fourth of the fin, and having a 

 white outer border. Other fius stained grey at their edges. 



Hub. East coast of Africa, Mauritius, Ceylon, to the Malay 

 Archipelago ; attaining to over G inches in length. 



894. (3.) Acanthurus aurolineatus. 



Acanthurus aurolineatus, Day, Fish. India, p. 204, pi. xlviii, fig. 3. 

 D. 9/26. P. 18. V. 1/5. A. 3/25. C. 17. 



Length of head 4|, of caudal 5 3, height of body 2| in the total 

 length. Eyes high up, diameter 3 in length of head, lg diain. 

 from end of snout, and 1 apart. Preopercle entire. Upper 

 profile of head rather convex. Teeth eight, lobate on either side 

 in the upper, and eight or nine in the lower jaw. Fins last 

 dorsal spine f of height of body and of about the same length as 

 the rays ; last portion of fin and of anal rather angular, inter- 

 spinous membrane very slightly emarginate. Pectoral about as 

 long as the head ; third anal spine rather above half the length of 

 the head. Caudal emarginate. Scales on head minute, very 

 small on the body, about t\\ euty rows between lateral line and 

 base of last dorsal spine. Lancet-shaped spine with a posterior 

 process. Least depth of the free portion of the tail equal to 1 

 diameter of the orbit. Colour general tinge yellowish, with 

 yellow horizontal lines along the body about half the width of the 

 ground-colour, which is bluish. A narrow lightish band over the 

 base of the caudal. Dorsal and anal fins bluish, with several 

 longitudinal yellow bands as on the body. 



Hob. Coromandel coast of India. 



895. (4.) Acanthurus triostegus. (Fig. 54.) 



Chaetodon triostegus, Linn. Si/st. Nat. i, p. 403. 



Acanthurus triostegus, Day, Fish. India, p. 204, pi. xlviii, fig. 2 (see 



synon.). 

 Mootah, Tel. ; Kara-pamooicah, Cing. 



D. 9/23-25. P. 15. V. 1/5. A. 3/20-22. C. 17. 

 Length of head 3| to 4, of caudal 5, height of body 2j to 2 in 

 the total length. Ei/es diameter 3| in length of head, 2 to 2 2 

 diam. from end of snout, and 1 to 1 apart. Profile from above 

 the orbit to the snout rather concave. Teeth eight lobate incisors 

 on either side of upper jaw, and nine or ten on either side ot 

 lower. Fins dorsal spines moderately strong, the last higher 



