214 Bulletin 47, United States National Museum. 



341. HYBOGNATHtS ABGYRITIS, Girard. 



Mouth wider than in H. nuchalis, its cleft reaching to opposite front of 

 eye ; jaws subequal, the lower acutish at tip ; suborbitals broad, the 

 anterior about twice as long as deep. Silvery. Length 4 inches. Very 

 close to H. nuchalis into which it may intergrade. Upper Missouri region 

 and Red River of the North, (argyritis, ap-yvptns, silvery.) 



Hybognafhus argyriti*, GIRARD, Proc. Ac. Nat. Sci. Phila., 1856, 182, Milk River. 

 342. HYBOGNATHTJS HAYI, Jordan. 



Head 4f ; depth 4 ; eye 3| ; snout 4. D. 8; A. 8 ; scales 5-36-3 ; teeth 

 4-4. Body rather slenderer than in H. nuchalis, the profile more rapidly 

 declined. Head small and low ; snout short, less obtuse than in nuclialisj 

 eye large ; maxillary 5 in head, not quite reaching eye ; suborbital bones 

 very narrow, the anterior 3 times as long as deep. Scales and fins essen- 

 tially as in H. nuchalis ; color the same ; intestine shorter, 4^ to 7-J times 

 body. Length 4 inches. Lower Mississippi and neighboring rivers, 

 known from Pearl River, from Memphis, Tennessee, and from streams in 

 Mississippi. Perhaps a variety of H. nuchalis. (Named for Dr. Oliver 

 P. Hay, discoverer of the species.) 



Hybognatlms argyritis, HAY, Bull. TJ. S. Fish Comm., n, 1882, 68, not of GIRARD ; JORDAN & GIL- 

 BERT, Synopsis, 968, 1883. 



Eybognalkus liayi, JORDAN, Proc. U. S. Nat. Mus., 1884, 548, Pearl River, Jackson, Missis- 

 . sippi. (Type, -No. 32306. Coll. Hay.) 



Subgenus DIONDA, Girard. 



843. HYBOGNATHUS SERENA (Girard). 



Head 4f ; depth 4 ; eye 3J-. D. 8 ; A. 8 ; scales 5-32 to 34-3. Eye large, 

 a little less than interorbital width. Ventral fin nearly reaching vent. 

 Color dusky, with a black lateral band ; fins plain. Length 2 inches. 

 Rivers of Western Texas ; with the next, from which it may be known by 

 the larger scales, (serenus, serene.) 



Dionda serena, GIRARD, Proc. Ac. Nat. Sci. Phila., 1856, 177, Sabinal River, Texas. (Tjpe, 

 No. 43. Coll. Kennorly.) 



Dionda papalis, GIRARD, Proc. Ac. Nat Sci. Phila., 1856, 178, Delaware Creek, a tributary 

 of Pecos River, Texas. (Coll. Capt. Pope.) 



Dionda chnjsitis, GIRARD, Proc. Ac. Nat. Sci. Phila., 1856, 178, Live Oak Creek, a tributary 

 of Pecos River. (Coll. Clark.) 



Hybognathusni^rotseniata, COPE, Bull. U. S. Nat. Mus., xvn, 37, 1881, Wallace Creek, a tribu- 

 tary of Medina River, Texas ; JORDAN & GILBERT, Synopsis, 156, 1883. 



344. HYBOON ATHUS EPISCOPA (Girard). 



Head 4i; depth 4|to 4|; eye large, 2f to 3i. D. 8; A. 8; scales 9-37 to 41-4. 

 Slender, fusiform in profile, and compressed, with the back slightly 

 arched. Head large, the snout decurved to the small, terminal mouth, the 

 maxillary reaching about half way to the eye. Dusky above, a blackish 

 band along the sides, ending in a dusky blotch at base of caudal; fins 

 yellowish, unmarked; scales with fine black dots. Length 3 inches. 

 Rivers of Western Texas and Northeastern Mexico from Rio Comal to Rio 



