31. CYPRINID^E HYBOGNATHUS. 157 



less than one-third the length of the head and a little less than the in- 

 terorbital width. Ventral flu nearly reaching vent. Color dusky, with 

 ji black lateral band. Fins plain. Head 5 in length, with caudal ; 

 depth the same. D. 8; A. 8; scales 5-34-3. L. 2 inches. Medina 

 Eiver, Texas. (CopCj MSS.) 



aa. Suborbital boucs short and deep. 



16. 19. pBacitus Grd. 



Head short and bluntish. Body stoutish. Eye small, shorter than 

 snout, about 5 in head. Scales moderate, about 10 in front of the dor- 

 sal. Size comparatively small. Grayish above, silvery below. Head 

 4f ; depth 4. D. 8; A. 7; Lat. 1. 40; teeth 4-4. Mississippi Valley to 

 Utah. (Possibly two species are here included.) 



(Girard, Proc. Acad. Nat. Sci. Pliila. 1856, 182: Hylognathus nuchaUs Cope, Proc. 

 Araer. Phil. Soc. Phila. 1874, 6(5: Hybognathus nuclialis Jordan, 289; probably not of 

 Agassiz.) 

 aaa. Suborbital bones unknown; small species of the Texan region. 



IN 1 ?. II. episcopus (Grd.) Jordan. 



Slender and graceful, fusiform in profile, and compressed, with the 

 back slightly arched. The head is large, forming about the fifth of the 

 length. Eye large and subcircular, the diameter 3i in head. Eins 

 moderate. Scales large, the lateral line following the middle of the 

 flanks. Dusky above, a blackish band along the sides, ending in a 

 dusty blotch at base of caudal. Fins unmarked. Scales with fine 

 black dots. D. 8; A. 8; Lat. 1. 39. L. 3 inches. Kivers of Texas. 

 (Girard.) This or some very similar species occurs in Southern Illinois. 

 (Forbes.) \ 



(JDionda episcopa, serena, texensis, papalis, argentosa, and chrysitis Girard, Proc. Acad. 

 Nat. Sci. Phila. 1856, 177-178.) 

 1. II. fltivaatilis (Grd.) Jor. 



Form, size, and coloration of H. amarus, but the mouth and eye 

 smaller and the scales smaller. D. 8; A. 7; Lat. 1. 40; 1C scales before 

 dorsal. Snout tubercnlate in spring males. New Leon. (Girard.} 



(AJgoma fluviatilis Grd. Proc Acad. Nat Sci. Phila. 1856, 181.) 

 ** Body short, deep, compressed, the depth about two-sevenths of the length. 



19. H. mclanops (Grd.) Jor. 



Head moderate, 4-| in length. Snout rounded. Eye medium. Black- 

 ish above; sides smoky, with black dots; a black spot at base of caudal. 

 Depth 3. D. 8; A. 7 ; Lat. 1. 43; teeth 4-4. L. 2 inches. Eio Grande 

 region. (Girard.) 



(Dionda melanops and coucM Grd. Proc. Acad. Nat. Sci. Phila. 1856, 178; Jordan, 

 Bull. U. S. Geol. Surv. iv, No. 2, 402.) 



