174 Bulletin 47, United States National Museum. 



DECACTYLUS, (<5e'a, ten; SaxrvAo?, toe, i. e., ventral rays): 

 bb. Scales small, but larger than in the preceding group, the number in the lateral line 



56 to 75. 



/. Scales in lateral line 70 to 75; lower lip broad. 

 g. Dorsal fin moderate, of 11 to 13 rays. 



h. Dorsal fin short, higher than long; head rather bluntish, 4% in length. 



LABIATUS, 285. 



hh. Dorsal fin longer than high. 



i. Scales before dorsal about 40; head conical, small, 4% in length. 



OCCIDENTALS, 286. 



. Scales before dorsal 31; head larger, 4% in length. 



BERNARDINI, 287. 



gg. Dorsal fin long, of about 15 rays, head large, the lips very full. . . 



MACROCHEILUS, 288. 



ff. Scales in lateral line 58 to 70; lips with about 4 rows of papillse. 



j. "Nose" little developed, not projecting much beyond the moderate mouth; 



mandible nearly horizontal. 



k. Dorsal moderate, scarcely higher than long, its base 1% to If in head; 

 the rays 11 to 13. 



I. Mandible 3% to 3% in head; upper lip narrow, with usually but 3 to 5 



rows of papillae, the number greater in western specimens (var. 

 sucWi); scales 10-64 to 68-9, crowded anteriorly. 



COMMER80NII, 289. 



II. Mandible 3 to 3% in head; upper lip broader, with 4 to 6 rows of 



papillae; scales 9-63 to 71-9, crowded anteriorly. ARDENS, 290. 



Tck. Dorsal short, distinctly higher than long, its base 1% in head, its rays 11 or 



12; upper lip with 4 to 6 rows of papillae. 



?w. Scales small and crowded anteriorly, 59 in lateral line; fontanelle large. 



GILA, 291. 



mm. Scales larger, little crowded anteriorly, about 56 in the lateral line, 

 each with a dark spot at base; fontanelle small. 



INSIGNIS, 292. 



Jj. "Nose" largely developed, slender and projecting at an angle beyond the 

 profile, its length 2% in head; mouth small, inferior, the lips smoothish; 

 D. 11 or 12; scales 64. (Approaches Chasmistes.') FECUNDUS, 293. 



HYPENTELIUM, (viro, below; ire'vre, five; labium, lip, "lower lip five-lobed"): 

 aa. Head broad, depressed, and transversely concave between orbits; scales nearly equal over 

 the body, not crowded anteriorly 48 to 55 in the lateral line; lips very thick; lower 

 fins large. 



n. Head large, 4 to 4% in length ; interorbital space concave. NIGRICANS, 294. 



nn. Head very small, 5 in length; interorbital space flattish. RHOTHOSCUS, 295. 



Subgenus CATOSTOMUS. 

 279. CATOSTOMUS LATIPINNIS, Baird & Girard. 



(FLANNEL-MOUTHED SUCKER.) 



Depth 5i in the length. Head moderate, 4| in length, rather slender, 

 with prominent snout and rather contracted, inferior mouth ; outline of 

 the mouth triangular, the apex forward ; lips very thick, greatly de- 

 veloped; lower lip incised to the base; its posterior margin extending 

 backward to opposite the eye ; tubercles on lower lip smaller behind ; 

 jaws with a slight cartilaginous pellicle. Eye small, high up; the head 

 flattish above. Scales long and low; posteriorly rounded, their horizontal 

 diameter greater than the vertical, 17-98 to 105-17. Body slender and 

 elongate ; the caudal peduncle long and slender. Fins excessively 



