16 CENTKARCHUS IRIDEUS. 



outlines being arched alike, and is much compressed. The head is small, though 

 broad above, and the facial outline slightly incurved, with the snout broad. The 

 eye is very large, prominent, and is placed half the diameter of its orbit from the 

 snout, and rather more than one diameter from the tip of the opercle, with its in- 

 ferior margin at the middle plane of the head. The nostrils are very near the eye, 

 and are on a line within the orbit. 



The mouth is very small, and the lower jaw is longer than the upper, though 

 its teeth are received within it when the mouth is closed. The group of inter- 

 maxillary and inferior maxillary teeth are small, closely set, pointed, recurved, with 

 an outer row of slightly larger teeth ; the pharyngeal bones are closely studded 

 with minute, short, and pointed teeth ; the vomerine teeth, as well as the palatine, 

 are equally minute ; and the tongue has a small patch of similar teeth. The pre- 

 opercle is but slightly rounded at its angle, where it is naked, and minutely ser- 

 rated. The opercle is rather broad, and sustains a short fleshy appendix. The 

 sub-opercle is long, naiTow, and has a single row of large scales; the head above, 

 from the middle of the orbits, is smooth, but the cheeks are covered with scales. 



The dorsal fin arises behind the root of the pectoral, is very large, and elevated, 

 especially in its soft portion; it has twelve spines and fourteen branched rays. 

 The pectoral begins at the opercle^ ends at the root of the sixth anal spine, and has 

 twelve rays. The ventral fin begins rather in front of the dorsal, and termi- 

 nates with the root of the fifth anal spine ; it has one spine and five soft rays, the 

 anterior of which is prolonged. The anal is as large as the dorsal fin, and is of the 

 same form ; it has eight spines and fifteen branched rays. The caudal is large, 

 broad, nearly entire, and has seventeen rays. The scales are large. The lateral 

 line corresponds to the curve of the back, and is placed about the superior fourth 

 of the body. 



Colour. The cheeks and sides of the head are of greenish-yellow ; the head 

 above, and the back, are dusky, with a greenish tint ; the sides are white, with 

 bluish-green spots, arranged in interrupted lines ; the pectoral and ventral fins are 

 transparent ; the dorsal and anal are semi-transparent, and marked with numerous 



