144 SHARK-TAILED HYPOSTOMA. 



having the sharp points of each of a deep brown co- 

 lour, so much so as to influence the tint of the part. 

 The mouth is rounded, and is furnished with a large 

 labial disk, having at each angle' a cirrhus of about 

 three-eighths of an inch in length. The teeth are 

 fine, sometimes notched at their cutting points, and 

 are placed upon moveable stalks. The whole body 

 above the angular line running from the opercula 

 to the tail is spotted over with black or brownish 

 spots, more minute and thicker on the head, and 

 appearing very conspicuous between the membranes 

 of the fins, where they have a brown appearance 

 and are of a larger size. The development of the 

 fins is considerable ; all the rays are rough ; the first 

 ray of the pectoral fin armed towards its extremity 

 with spines fully a quarter of an inch in length, 

 apparently having the same structure and crooked 

 tips as in Acanthicus. In the caudal fin the rays 

 are strong, those on the outsides powerful; the 

 lower exceeds the upper in length by at least one- 

 half, and is strongly spined at its extremity. 

 Formula of the fins is, 



D. 1/7— 2d D. 1_P. 1/6— V. 1/5— A. 1/4— C. 2/12. 



No. 68, Schomb. Drawings, represents another 

 small Hypostoma, which we do not refer to any 

 described species ; it belongs apparently to the 

 second division, or to those with a tuft of spines 

 upon the inter-operculum. 



