eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 471 



317. Nebris microps Cuvier and Valenciennes. 

 Nebris microps Cuvier and Valenciennes, Hist. Nat. Poiss., V, 1830, 149, pi. 112 

 (Surinam).— Gunther, Catalogue, II, 1860, 316 (copied).— Steindachner, 

 " Ichthyologische Beitrage," iv, 1875, 10 (Bay of Panama). — Jordan and Gil- 

 bert, Bull. U. S. Fish Com., II, 1882, 111 (Panama). — Jordan and Eigen- 

 mann, Rept. U. S. Fish Com. for 1886, 1889, 374 (Panama).— Jordan and 

 Evermann, Rept. U. S. Fish Com. for 1895, 1896, 395 (name only).— Vail- 

 lant, Bull. Mus. d'Hist. Nat., Ill, 1897, 124.— Jordan and Evermann, Bull. 

 U. S. Nat. Mus. No. 47, II, 1898, 1417.— Vaillant, Notes Leyden Mus., 

 XX, 1898, 17-20 (Guyane); Nouv. Arch. Mus. d'Hist. Nat., (4), II, 1900, 

 135 (Surinam). — Hargreaves, Fishes of Brit. Guiana, Appendix, 1904, 2. 

 Seven specimens, 200-314 mm. Georgetown market. (C. M. Cat. No. 

 2469a-d; I. 17. Cat. No. 12567.) 



Head 3-3.5; depth 4; D. VIII-1,32 to 34; A. 11,11; scales 50 with pores, 

 100 above the lateral line to the base of the caudal; eye 9.5-10 in the head; inter- 

 orbital region very broad, convex, 3-3.2 in the head. 



Compressed, elongate; head very thick. Mouth very large and oblique. 

 Lower jaw prominent; teeth villiform, in several series above, in two or more 

 series below. Gill rakers 7 + 15. Scales generally cycloid, but somewhat ctenoid 

 over the body cavity in the larger specimens. Scales along the lateral line run- 

 ning to the end of the caudal rays not enlarged. Soft dorsal, anal, and caudal 

 much thickened with small scales. Spinous dorsal very weak; anal spines almost 

 indistinguishable. 



Color light, silvery on the head. Five broad, dusky bands across the back 

 and sides, above the lateral line, quite distinct in the large specimens, only indi- 

 cated in the smaller ones. Spinous dorsal, tips of soft dorsal rays, more or less of 

 the caudal, tips of the anal rays, tips of the ventrals and inner side and tips of the 

 pectorals, all dusky. Axil dusky in adults. 



Plagioscion Gill. 

 Plagioscion Gill, Proc. Acad. Nat. Sci. Phila., 1861, 82 (description of genus only). 

 Diplolepis Steindachner, "Scisenoiden Brasiliens," etc., in SB. Akad. Wiss. Wien, 



XLI, 1863, 2 (squamosissimus) (name preoccupied in Hymenoptera). 

 Plagioscion Jordan and Eigenmann, Rept. U. S. Fish Com. for 1886, 1889, 380 



(squamosissimus) . 



Type, Scicena squamosissima Heckel. 



A genus of fresh-water fishes in the rivers of South America, separated from 



