490 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



spine. Maxillary barely reaching' to opposite the large eye; eyes high 



up, sei>arated by a narrow, grooved space. Pectorals short, reaching- 



tips of ventrals, half way to vent. Head 4^; depth 7. D. X-10; A. 



I, 85 Lat. 1. about 75, about 6 series of scales above it. L. 3 inches. 



Ohio valley and northwestward ; abounding in clear sandy streams ; one 



of the most interesting of our fishes. 



{Etlicosioma pclhtcidum BairdMSS.: Plevrolejns peUucidus Agasaiz, Bull. Mus. Comp. 

 Zool. i, 5, 1860: Pleurolcjiis pellucidus Vaillant. Recherclies sur Etlieostom. in Nouv. 

 Arcliiv. Mns. 1874, 138 : PJeurolepis pellucidus Jordan, Man. Vert. ed. 2, 219 : Plcurolepis 

 pellucidus Jordan & Copeland, Amer. Nat. 1877, 86.) 



■yes. A. asprella Jordan. 



Head long, rather slender. Eyes very large, high up and very close 

 together. Mouth not large, sub-termiual, horizontal. Cheeks and oper- 

 cles with pectinated scales. Opercular spine w^ell developed. Squama- 

 tion much more complete than in A. jjeUucida, the scales small and 

 quite rough, largest posteriorly. Throat and belly naked, the space 

 between the ventral fins scaled. Back of neck scaly. Fins large, the 

 dorsals well separated; the spinous high, highest in front; second dor- 

 sal smaller, smaller than anal; anal spine high, flexible; caudal lunate. 

 Coloration clear olivaceous, sides with 8 to 10 dark squarish blotches, 

 quite small and far apart; a blackish shade forward from eye, and a 

 dusky shade across oi)ercle. Said to present in life '^ almost all the 

 colors of the rainbow." Head 4^; depth 8. D. IX-10; A. I, 8; Lat. 1. 

 98, ten series above the lateral line. L. 4 inches. Illinois to Alabama, 

 in sandy streams; a much larger and rougher si)ecies than the preceding. 



{Plcurolepis asprellus Jordan, Bull. Ills. Lab. Nat. Hist. 2, 38, 1878: Pleurolepls as- 

 prcllus Jordan, Man. Vert. ed. 2, 404.) 



253.— I®A Jordan & Braytou. 

 (Jordan & Brayton, Bull. U. S. Nat. Mus. xii, 88, 1878: type Pcecilichilujs <utreus Cope.) 



This genus differs from Ammocrypia chiefly in the presence of two well- 

 developed spines in the anal fin. Tlie anal fin is i)roportionately siualler, 

 and the scales are larger and rougher, more fully covering the body. 

 The squamation of the head is moie complete than in any other genus. 

 Species slender, translucent in life, {loq^ an arrow or dart.) 



764. I. vitB-ca (Cop<-) J. & B. 



Form of Ammocrijpta. Head slender, acuminate; mouth not very 

 small; temporal region scaled; cheeks and open^les covered with large, 

 imbricated, very roughly ctenoid scales, these scales extending forward 

 to the maxillary and backward to edge of opercle and on subopercle; 



