MOXOSTOMA.— CATOSTOMUS. 1*7 



3. MoxOStoma mascots, sp. n. (Tab. XXIV. fig. 2.) 



Pharyngeal teeth comparatively few and strong, about 6 on each side. Depth of body 4 to 41 in tbe length, 

 length of head 4 to 4|. Diameter of eye 5 to G in the length of head, length of snout 2| to 2|, 

 interorbital width 2i to 2|. Snout truncated anteriorly. Lips plicated ; lower lip with a straight 

 transverse posterior edge ; width of mouth f to 4 the width of head. 43 to 48 scales in a longitudinal 

 series, 6 or 7 in a transverse series from origin of dorsal iin 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 hack, extending nearly to the caudal. Pectoral shorter than the head, extending | to | 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 emarginato. Caudal peduncle 1| to 1| as long as deep. Brownish above, yellowish 

 below ; fins pale yellowish. 



Ilah. 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. Moxostonia parvidens, sp. n. (Tab. XXIV. fig. 3.) 



Pharyngeal teeth small, 14 on each side. Depth of body 3| to 4 in the length, length of head 4 to 4|. 

 Diameter of eye 3^ to 3| in the length of head, length of snout 3 to 3|, interorbital width 2i. 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 5 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 S, 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 iins pale. 



Ilab. Mexico, Rio Grande at Juarez [Woolman). 

 Two specimens, 90 and 120 mm. in total length. 



3. CATOSTOMUS, Le Sueur, 1817. 



Pardosteus (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 pkbeius, 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'. 



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