APHREDODERUS PIRATE-PERCHES 229 



spine; mouth somewhat oblique; premaxillary not protractile; maxillary 

 without evident supplemental bone; teeth in villiform bands on jaws, 

 vomer, palatines, and pterygoids; pyloric ca?ca about 12; intestinal canal 

 ending at throat in the adult, the vent more posterior in the young, mi- 

 grating forward, with growth, from just behind the ventral fins; air- 

 bladder simple, large, adherent, the duct probably obsolete. 



Fresh waters of the United States ; a single living genus and spe- 

 cies; several fossil genera. While the structure of the skeleton is 

 essentially that of percoid fishes, the character of the forward posi- 

 tion of the vent leaves the Aphredoderidcc singularly isolated, without 

 close relationships with the true perch-like forms. 



Genus APHREDODERUS Le Sueur 

 (pirate-perches) 

 Characters of the genus included above. 



*) 



Pig. 55 

 APHREDODERUS SAYANUS (Gilliams) 

 (pirate-perch) 



Gilliams, 1824. J. Ac. Xat. Sci. Phila., IV, .si (Scolopsis). 



J. & G., 460; M. V., 113; T. & E., I. 7S6; N., 39 (A. sayanus and Sternotremia 

 isolepis); J., 48 (Aphododerus isolepis) ; F., 70; L.. 22. 



Length 2 to 4 inches; body robust, rather deep and considerably 

 compressed, the caudal peduncle stout; depth 3 . 1 to 3 . 5; greatest width 

 scarcely more than h greatest depth ; depth caudal peduncle 1 . 6 to 1 . 9 

 in its length. Color dark olivaceous over transparent pinkish to laven- 

 der, the head and body everywhere profusely specked with black, ap- 

 pearing bluish over the ground color; under side of head and sometimes 

 fore part of breast and belly yellowish; two blackish bars at base of 

 caudal; fins, except ventrals, dusky with a more deeply pigmented band 

 around bases; ventrals yellowish; median fins with a narrow marginal 

 fringe of white. Breeding males and females show much iridescent 

 color, the predominating lusters being violet and purple; light coppery, 



