MOXOSTOMA.—CATOSTOMUS. 147 
3. Moxostoma mascote, sp. n. (Tab. XXIV. fig. 2.) 
Pharyngeal teeth comparatively few and strong, about 6 on each side. Depth of body 4 to 42 in the length, 
length of head 4 to 43. Diameter of eye 5 to 6 in the length of head, length of snout 23 to 23, 
interorbital width 23 to 23. Snout truncated anteriorly. Lips plicated; lower lip with a straight 
transverse posterior edge ; width of mouth 2 to 3 the width of head. 48 to 48 scales in a longitudinal 
series, 6 or 7 in a transverse series from origin of dorsal fin to lateral line, 5 or 6 from lateral line to 
base of ventral. Dorsal 12-13, the 2 anterior rays simple; origin equidistant from tip of snout and 
base of caudal or a little nearer the former; free edge of the fin straight or slightly concave; longest 
ray as long as or a little longer than the base of the fin. Anal 8, the 2 anterior rays simple, the fin, 
when laid back, extending nearly to the caudal. Pectoral shorter than the head, extending 3 to 2 of 
the distance from its base to the origin of the ventral, which is a little in advance of the middle of the 
dorsal. Caudal emarginate. Caudal peduncle 13 to 12 as long as deep. Brownish above, yellowish 
below ; fins pale yellowish. 
Hab. Mexico, Rio Mascota in Jalisco (Buller). 
Here described from seven specimens, 105 to 150 mm. in total length, taken near 
the source of the river, at a height of 4000 feet. 
4. Moxostoma parvidens, sp. n. (Tab. XXIV. fig. 3.) 
Pharyngeal teeth small, 14 on each side. Depth of body 32 to 4 in the length, length of head 4 to 4}. 
Diameter of eye 33 to 33 in the length of head, length of snout 3 to 34, interorbital width 24. Snout 
truncated anteriorly. Lips plicated; lower lip with the posterior edge notched, V-shaped, the two 
halves of the V meeting at an obtuse angle; width of mouth nearly 4 the width of head. 41 to 43 
scales in a longitudinal series, 6 in a transverse series from origin of dorsal fin to lateral line, 5 from 
lateral line to base of ventral. Dorsal 14, the 2 anterior rays simple; origin nearer to tip of snout than 
to the base of caudal; free edge of the fin nearly straight; longest ray as long as or shorter than the 
base of the fin. Anal 8, the 2 anterior rays simple, the fin, when laid back, extending to the base of 
caudal. Pectoral a little shorter than the head, extending ? of the distance from its base to the origin 
of ventral, which is below the middle of the dorsal. Caudal emarginate. Caudal peduncle as long as 
deep. Silvery, back brownish ; dorsal dusky ; other fins pale. 
Hab. Mexico, Rio Grande at Juarez (Woolman). 
Two specimens, 90 and 120 mm. in total length. 
3. CATOSTOMUS, Le Sueur, 1817. 
Pantosteus (Cope, 1876) and Catostomus, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, 
pp. 169 and 173. 
The distinctive characters of this genus are the short dorsal fin, small scales, complete lateral line, moderate 
inferior protractile mouth, jaws with cartilaginous sheaths and compressed pharyngeal teeth. 
There are about 25 species from North America and one from Eastern Siberia. 
1. Catostomus plebeius. 
Minomus plebeius, Girard, Rep. U.S. & Mex. Bound. Surv., Fish. p. 38, t. 22. figs. 1-4 (1859) *. 
? Acomus guzmaniensis, Girard, t. c. p. 39, t. 23. figs. 1-10°. 
Catostomus nebuliferus, Garm. Bull. Mus, Comp. Zool. viii. 1881, p. 89°. 
U2 
