208 Bulletin 47, United States National Museum, 



382. ACROCHEILUS ALUTACEUS, Agassiz & Pickering. 

 (CHISEL-MOUTH ; SQUARE-MOUTH ; HARD-MOUTH.) 



Head 4; depth 4; eye 5|. D. 10; A. 9; scales 20-85-16. Teeth 4-5, 

 hooked, somewhat club-shaped, with a broad grinding surface. Body 

 elongate, not much compressed; caudal peduncle very long and slender, 

 nearly terete. Head moderate, bluntish, the profile rounded, the inter- 

 orbital space strongly convex. Mouth horizontal, subinferior, overlapped 

 by the broad, blunt snout, its breadth considerable, but the maxillary 

 not extending far back, to opposite the front of the eye. Upper jaw pro- 

 tractile, covered with a fleshy lip, inside of which is a small, straight, 

 cartilaginous plate, similar to that on the lower jaw, but much smaller 

 and not evident externally; lower lip covered with a firm cartilaginous 

 plate, sharp externally, the upper surface being formed by its beveled 

 edge. The transverse width of this plate is between 4 and 5 times its 

 (longitudinal) breadth; the plate extends in nearly a straight line from 

 one angle of the mouth to the other; its transverse width is contained 

 2f times in length of head. Eye rather large, If in snout, its position 

 anterior and not high up, 2J in interorbital space. Dorsal long, rather 

 low, its first ray just behind first ray of ventrals, midway between snout 

 and middle of base of caudal ; caudal fin very long, the lobes about equal, 

 longer than head, widely forked, the accessory rays at its base very 

 numerous and recurrent on the caudal peduncle; about 8 of these may 

 be distinguished on each side of the fin. Anal fin rather large; ventrals 

 broad, reaching vent. Pectorals moderate, not reaching two-thirds of 

 the distance to the ventrals. Scales quite small, somewhat embedded in 

 the skin, very loosely imbricated, the exposed surfaces longer than high 

 profusely punctate; squamation quite irregular. The scales smaller on 

 back and belly than on sides, most exposed on caudal peduncle. Lateral 

 line much decurved. Coloration very dark; belly paler, but nearly all 

 parts of the body studded with minute dark points. Peritoneum black; 

 intestines much elongate, usually filled with vegetable substance. Length 

 12 inches. Lower Columbia River and tributaries, as far up as Spokane 

 and Shoshone Falls ; locally abundant, (alutaceus, leathery.) 



Acrocheilus alutaceus, AGASSIZ and PICKERING, Amer. Journ. Sci. Arts, xix, 214, 1855, Willamette 

 Falls and "Walla Walla River; GUNTHER, Cat., vn, 276 ; JORDAN, Proc. TJ. S. Nat. Mus., 

 1878, 83 ; JORDAN & GILBERT, Synopsis, 150, 1883. 



104. LAVINIA, Girard. 



Lavinia, GIRARD, PTDC. Ac. Nat. Sci. Phila., 1854, 137, (exilicauda). 



Body elliptical, elevated, moderately compressed, rapidly contracted 

 to the slender caudal peduncle. Head small, conical. Mouth moderate, 

 terminal, oblique; the lower jaw included. Scales moderate, not closely 

 imbricated, the exposed surfaces somewhat hexagonal. Lateral line 

 decurved, complete. Belly behind ventrals entirely scaled. Dorsal fin 

 well behind ventrals, its last ray just in front of beginning of anal, 

 which is rather elongate. Caudal fin little forked, its rudimentary basal 

 rays much increased in number and very strong. Intestinal canal elon- 

 gate, 3 times the total length of the fish ; peritoneum dark. Teeth 4-5 or 



