‘206 CONTKII5UTIONS TO NOETII A:MERICAN ICHTHYOLOGY IV. 
Hayden’s Geol. Surv. Wyom. 1870, 440, l«7;i ; Jordan, Bull. Hayden’s Geol. Surv. Terr, 
iv, No. 3, 0(5;) (a rather chubby spceinieu Ironi the Rio Grande, with scales 6-45-7, 
the breast naked, is referred by us to this species) : f Phmacohius teretuhis var. liosternua 
Nelson, Bull. Ills. Mus. Nat. Hist, i, 1876, 46.) • 
** Scales small, about 60 in the lateral line. 
3 3 1. P. catosSomiis Jordan. 
Body ratlicr slender, nearly terete, scarcely compressed at all, back 
not elevated, caudal peduncle stout. Head very large, the muzzle blunt 
and heavy, the cheeks tumid. Mouth small, inferior, altogether below 
the level of the eye, the maxillary barely reaching to the nostrils. Eyes 
large, high up, behind middle of head, and in its length. Scales 
small, thin, and loosely imbricated ; the back and belly scaled ; chest 
naked. Lateral line nearly straight. Twenty-two scales in front of 
dorsal. Fins all small. Width of isthmus 2^ in head. Pale oliva- 
ceous; white below; a silvery lateral band, underlaid by dusky, which 
forms a vague blotch at base of caudal ; back dusted with dark specks; 
top of head black; a yellowish vertebral line. . Head L}; depth 5|. D. 
8; A. 7; scales 7-C0-5; teeth 4-4. L. 4 inches. Alabama River. 
(Jordan, Ann. Lyc. Nat. Hist. N. Y. 1876, 332.) 
312. P. uraeiops Coi)e. 
Body very slender, little compressed, back not elevated, caudal pe- 
duncle long and slender. Head long and rather slender, flat above, 
the muzzle broad, blunt, and projecting. Mouth entirely inferior, larger 
than in the other species, with conspicuous lips. Eye large, placed very 
high, behind the middle of the head, 3^ in head. Scales small, 24 in 
front of dorsal. Lateral line straight. Chest and middle line of belly 
naked. Width of isthmus half length of head. Fins small. Head 4^; 
depth 6. D. 8; A. 7; scales 7-GO-O; teeth 4-4. Tennessee River. 
(Cope, Proc. Acad. Nat. Sci. Phila. 1867, 96.) 
§9.— Agassiz. 
Blacic-nosed Dace. 
{Argyreua Heckel, preoccupied in Entomology.) 
(Agassiz, Lake Superior, 1850, 353: type Cyprinus atronasus Mitchill.) . 
Body rather elongate, not much compressed. Mouth small, subin- 
ferior, normal, the upper jaw not protractile, the uiiper lip continuous 
with the skin of the forehead, a barbel terminal on the maxillary. 
Teeth mostly 2, 4-4, 2, hooked, without grinding surface. Intestinal 
