Percesoces and Rhegnopteri 225 



sometimes longer than the body. Two of the actinosts of the 

 pectoral support the fin, one is slender and has no rays, while 

 the fourth is plate-like and attached to the coracoids, support- 

 ing the pectoral filaments. The body is rather robust, covered 

 with large scales, formed much as in the mullet. The lateral 



FIG. 178. Shoulder-girdle of a Threadfin, Polydactylus approximans 

 (Lay & Bennett). 



line extends on the caudal fin as in the Sci&nidce, which group 

 these fishes resemble in many ways. The mouth is large, 

 inferior, with small teeth. The species are carnivorous fishes 

 of excellent flesh, abounding on sandy shores in the warm 

 seas. They are not very active and not at all voracious. The 



FIG. 179. Threadfin, Polydactylus octonemus (Girard). Pensacola. 



coloration is bluish and silvery, sometimes striped with black. 

 Most of the species belong to the genus Polydactylus. Poly- 

 1115 



