20 SQUAJIIPINNES. 



Descr'qytion. — This species is closely allied to Ch. rohushis, but may 

 be readily disting-uished by a dift'erent arrangement of the cross-bands, 

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

 The greatest height of the body is li in the total length. The 

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

 very slightly concave above the orbit. The lower profile exliibits 

 scarcely any concavitj'. The snout is slightly produced, as long as 

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

 angle of the pra3operculum 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 tlu'ee being equal and rather shorter than 

 the fii'st 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 foui'th 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 eoloiu's 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 wliite, 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 foiuih dorsal spine 1 0| 



of the second anal spine , 11 



31. Chsetodon gracilis. 



D.if. A.^. L. lat. 38. L. transv. 7/17. 



The snout is moderately produced and somewhat conical ; the 

 angle and the lower margin of the pra^operculum very slightly den- 

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

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

 the interoperculum ; a brown, white-edged vertical band fi-om 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 Inches. From Mr. Scrivener's Collection. 

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



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



