48 CENTROPRISTES TRIFURCA. 



directed a little forwards, and finely serrated. The opercle is sub-triangular, pro- 

 longed behind in a round fleshy appendix, and furnished with tAvo flat spines 

 placed near together ; the superior is large, and the inferior minute. The head is 

 covered with scales, except the snout, cheeks, and under the eyes to the upper jaw, 

 and between the eyes ; those of the opercle are large, except near the angle, where 

 they are small. The gill-openings are very extensive ; there are seven branchial 

 rays ; the supra-scapular is small, but strongly serrated behind. 



The dorsal fin is long, and begins rather before the termination of the fleshy 

 opercle, and ends in a point at the root of the caudal; it has ten compressed, 

 slightly curved, sharp-pointed spines, of which the anterior is very short, the sec- 

 ond twice its length, and the third and fourth are double the length of the second ; 

 from this they gradually decrease to the tenth ; each spine has a delicate filament 

 appended to it, which in the third, fourth, and fifth are as long as the spines them- 

 selves ; the soft portion has eleven rays ; the seventh, eighth, and ninth are pro- 

 longed, and give a pointed form to the fin. The pectoral fin is long, broad, 

 rounded behind, and ends before the vent ; it has sixteen rays, with a semicircular 

 fold of skin in the axilla above. The ventral is short, rather broad, and begins 

 with the pectoral, but is shorter and has one spine and five soft rays. The anal is 

 very long ; it arises nearly opposite the root of the third dorsal soft ray, and ex- 

 tends almost to the root of the caudal ; it has three spines, the anterior very small, 

 and eight soft rays, of which the fourth, fifth, and sixth are prolonged like the 

 dorsal fin. The caudal is elongated, with sixteen rays ; those of the margin above 

 and below, as well as some of the central ones, are so prolonged as to give the tail 

 a tridentate appearance. 



The scales are rather large, sub-pentagonal, with two faces of the pentagon 

 meeting at a very obtuse angle behind, where it is finely but strongly serrated ; its 

 anterior margin has eight radiating striae. The lateral line is concurrent with the 

 back, and at about the upper third of the body ; its scale is sub-triangular, with its 

 base before, and its apex behind and rounded ; the tube is near its middle. 



