20 SQITAMIPINNES. 



Description. — This species is closely allied to Ch. rohustus, but may 

 be readily distinguished by a different an-angement of the cross-bands, 

 by the banded caudal fin, and by the different numbers of the fins. 

 The greatest height of the body is 1^ in the total length. The 

 upper profile descends abruptly from the origin of the dorsal, and is 

 very slightly concave above the orbit. The lower profile exhibits 

 scarcely any concavity. The snout is sHghtly produced, as long as 

 the diameter of the eye or as the distance between the orbits. The 

 angle of the praeoperculum is nearly a right one, and its lower margin 

 is slightly denticulated. The spines of the fins are rather strong : 

 those of the dorsal increase in length to the fourth, which is two- 

 thirds the length of the head ; the following gradually become shorter 

 to the eleventh, the last three being equal and rather shorter than 

 the first ray. The soft portion of the fin is not elevated and roimded 

 posteriorly. The caudal is truncated. The second anal spine is the 

 longest and strongest, rather shorter than the fourth dorsal spine. 

 The soft portion of the anal is very much like the corresponding part 

 of the opposite fin, but rather lower. The ventral reaches to, the 

 pectoral nearly to, the vertical from the vent. 



The scales are large, especially those in the middle of the side of 

 the body ; one of the largest covers five-sixths of the orbit. 



I may add to the description of the colours given above, that there 

 is an indistinct single brownish streak along the middle of the snout 

 and forehead; that the brown inframarginal band of the anal originates 

 at the base of the first spine : and that the greater portion of the 

 soft dorsal and anal are white, like the body (in spirits). 



inches, lines. 



Total length 5 4 



Height of the body 3 3 



Length of the head 1 6 



Diameter of the eye 5 



Length of the foiirth dorsal spine '.. 1 0| 



of the second anal spine 11 



31. Chsetodon gracilis. 

 D. 1?. A. l^. L. lat. 38. L. transv. 7/17. 



The snout is moderately produced and somewhat conical , the 

 angle and the lower margin of the praeoperculum very sliglitly den- 

 ticulated ; the dorsal and anal fins rounded posteriorly. The ocular 

 band is narrower than the orbit, edged mth white, and reaches over 

 the interoperculum ; a brown, white-edged vertical band from the 

 extremity of the dorsal across the tail over the posterior half of the 

 soft anal. The remainder of the fish whitish (in spirits). 



Caribbean Sea. 



a, h. Adult. West Indies, i'rom Mr, Scrivener's Collection. 

 c. Adult. West Indies. From Mr. Scrivener's Collection. 



Descriptton. — This species has the body moderately elevated, its 



