Jordan and Evermann, — Fishes of North America. 2235 



2503. AWAOCS FLATUS (Cuvier & Valenciennes). 



Head 4 ; deptli of to 6^ ; eye equal to the interorbital width, placed high. 

 D. VI-1, 12; A. 1, 10; scales about 53 to 55, little crowded auteriorly, 21 

 before the dorsal. Mouth horizoutal, maxillary extending to middle of 

 eye, 2^ iu head; lower jaw flatter than in Aivaous taiasica; teeth small, in 

 narrow bauds, those of the outer row enlarged ; some large teeth in band 

 of lower jaw. Yellowish, with a row of faint ocellated spots along middle 

 of sides ; dorsal and caudal faintly barred ; lines radiating from eye, a 

 line along opercle halfway to pectoral, sometimes uniform blue-black. 

 Rivers of Surinam and Brazil, south to Bahia. (flavus, yellow.) 



Gobiusjlavus, CuviER & Valenciennes, Hist. Nat. Poiss., xii, 60, 1837, Surinam ; Gunthee, 



Cat. Fish., in, 13,1861. 

 Chonophorus flavus, Jobdan & Eigenmann, I. c, 500; Eigenmann & Eigenmann, I. c, 67. 



2564, AWAOCS NELSOIVI, Evermann. 



Head 3^; depth 6; eye 5fiu head; snout 3; maxillary 2|. D. YI-11; A. 

 11 ; scales about 63. Body long, compressed and tapering posteriorly ; head 

 large, quadrate, mouth nearly horizontal, lower jaw included; snout 

 abruptly decurved; top of head flat, the interorbital with a slight median 

 groove with a thin, raised edge on each side; maxillary reaching about to 

 vertical of anterior edge of pupil; teeth in bauds on jaws very small, 

 the outer somewhat enlarged; pectoral rays normal, the longest 1^ iu 

 head; veutrals completely united, the disk free from belly. If in head. 

 Dorsal fins separated by a space about f diameter of eye ; dorsal spines 

 slender, weak, about 1| in head; soft dorsal and anal similar, each free 

 from caudal; caudal fin rather short and rounded, its middle rays about 

 l:]r iu head. Gill membranes broadly united to the isthmus; eyes mod- 

 erate, high up, the interorbital width equal to the eye's diameter. Scales 

 ctenoid, very small and irregularly crowded anteriorly, much larger pos- 

 terioily, about 15 rows counting from origin of soft dorsal downward and 

 backward to the anal fin; head naked, but with slight indication of a 

 few minute embedded scales on opercles. Color grayish ; head mottled 

 and blotched with dark; side with 7 or 8 black blotches, the largest 

 under middle of pectoral fin ; dorsals pale, crossed by several lines of black 

 spots; caudal pale, with al)0ut 6 or 7 dark cross bars; ventrals and anal 

 pale; pectorals pale, dusted with dark specks and with a small dark 

 blotch at base of upper rays. Close to A. taiasica, but with broader inter- 

 orbital, longer snout and larger scales on posterior jjart of body. Length 

 4 inches. Known only from fresh water at Rosario, Siualoa, where 8 speci- 

 mens were obtained July 27, 1897, by Mr. E. W. Nelson. (Named for Mr. 

 Edward William Nelson, the well-known ornithologist, in recognition of 

 his work upon the fishes of Illinois in 1876.) 



Aivaous nelsoni, Evermann, Proc. Biol. Soc. "Waahington, vol. xii, 1898, 3, fresh-water 

 pools at Rosario, Sinaloa, Mexico. (Type, Xo. 48836, U.S. Nat. Mua.; cotypes, No. 

 533 U. S. Eish Comni., 5793 L. S. .Tr. Univ. Mna., and 48837 U. S. Nat. Mua.) 



