DORAS COSTATUS. 157 



probable that, as in other fishes, these rays may 

 lot, so far as number is concerned, be a cer- 

 tain specific character. In the dried specimen, and 

 from the description of Valenciennes, the colours 

 may be stated as of a dull brown, clearer along the 

 centre of the costal plates, and upon the lower part 

 of the head and strong rays of the fins. In the 

 drawing before us, however, the whole fish is repre- 

 sented of a deep gi-eenish blue, paler and tinted 

 with yellow upon the lower part of the head and 

 rays of the fins, and very much darker upon the 

 whole of the plates covering the upper part of the 

 head ; the line running along the centre of the body 

 and the spines are nearly white, and relieve the dull 

 tint of the other parts. The eye is coloured chestnut- 

 red. Dr. Hancock describes his Doras costatus to be 

 brownish grey. Yalenciennes considers Hancock's 

 Doras as new, and gives it the appellation of Z). 

 Hancock'ii^ * and from the descrepancy of the de- 

 scription in the Zoological Journal, and in the for- 

 mula of the fins given above, we are inclined to 

 agi'ee in its distinction. The accompanying notes 

 observe, " This species resembles the last (the spe- 

 cies we next describe), but grows to a foot in length ; 

 the tail is rounded ; adipose fin situate over the 

 anal, to which the anus is near. The body is 

 round ; cranium covered with bony plates, serrated 

 at the edges, and ending in the middle in a long 

 spine ; a white stripe runs along the middle, where 

 these spines are situate. The air-bag is double,^- 

 * Vol. XV. p. 279. 



