220 APPENDIX F. FISHES. 



rial diameter being contained three times and a half in the length of the 

 sides of the head. The mouth is rather small, its angle not extending 

 to a point below the anterior rim of the eyes. The opercular bone is 

 conspicuously large, and almost trapezoidal in shape. The subopercu- 

 lar and preopercular are comparatively small. The isthmus beneath is 

 about three-tenths of an inch wide. 



The dorsal fin is longer than high, and is composed of nine rays, bi- 

 furcated from about their middle ; some of the median rays showing 

 another subdivision upon their extremity. The caudal fin is forked ; its 

 angles are acute. It contains eighteen well-developed rays, and several 

 rudimentary ones above and below ; the central ones bifurcate twice. 

 The base of the caudal fin is considerably broader (higher) than the 

 central portion of the peduncle of the tail. The anal fin is situated be- 

 hind the dorsal, is higher than long, subtrapezoidal, and composed of 

 eight bifurcated rays; the central ones subdivided towards their extremity. 

 The ventrals are inserted very little behind the anterior margin of the 

 dorsal ; they are rather slender, posteriorly rounded, composed of eight 

 bifurcated rays, the middle ones bifurcated towards their extremity; and 

 when bent backwards the fin does not reach quite to the anus, which 

 is situated immediately in advance of the anterior margin of the anal 

 fin. The pectorals are slender ; when bent backwards they do not reach 

 the insertion of the ventrals. They are composed of fourteen bifurcated 

 ravs, the central ones subdividing at their last third. Formula : 

 D 9 ; A 8 ; G 3. I. 8. 8. I. 3 ; V 8 ; P 14. 



The scales are proportionally large, a little higher than long, rounded 

 at both ■ extremities, more abruptly posteriorly. The lateral line runs 

 along the middle of the side, slightly bent downwards on the abdomen. 



The ground-color is yellowish brown ; a blackish stripe composed of 

 crowded dots follows the lateral line on the sides. 



One specimen (immature) caught in Otter creek, Arkansas. 



Plate XIV, fig. 1, represents Leuciscus vigilax, size of life. 



Fig. 2. A dorsal scale. 



Fig. 3. A scale from the lateral line. 



Fig. 4. Abdominal scale. ' 



Figs. 2-4 are enlarged twelve times. 



4. Leuciscus bubalinus, B. & G-. 



Zoology, PI. XIV, figs 5-8. 



Spec. char. — Compressed. Back arched. Tail slender. Dorsal fin 

 higher than long. Ten rows of scales across the line of greatest depth, 



