146 OSTARIOPHTSI. 



1. Moxostoma coiigestum. 



Plychos/omus congestus, Girard, Kep. U.S. & Mcx. Bound. Surv., Fish. p. 36, t. 21. figs. 5-8 (1859) \ 



Ptychostumus alhidtis, Girard, t. c. p. 36, t. 19. figs. 5-8'-. 



Moxostoma coiigestum, Jord. & Evcrm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 192, and J 900, 



f5g. 91 \ 

 Mij:ostoma congestum, Meek, Publ. Columl)ian Mus., Zool. v. 1904, p. 34 '. 



Depth of bod}- 4 in the length, length of head 4 to 4,5-. Diameter of eye 4 to 4^ in tlio length of head, length 

 of snout 2|, intororbital width 2 to 2>J-. Snout truncated anteriorl}'. Lips plicated ; lower lip with a 

 straight transverse posterior edge ; width of mouth -J- to i the width of head. 44 to 4G scales in a 

 longitudinal series, G or 7 in a transverse series from origin of dorsal fin to lateral line, 5 or G from 

 lateral line to base of ventral fin. Dorsal 12, the 2 anterior rays simple ; origin nearer to tip of snouf 

 than to base of caudal ; free edge straight or slightly concave ; longest ray longer than the base of tho 

 fin. Anal 8, the 2 anterior rays simple, the fin, when laid back, extending to the basal part of the 

 caudal. Pectoral as long as the head, nearly or quite reaching the ventral, which is inserted below 

 the anterior part of the dorsal. Caudal emarginate. Caudal peduncle Ik as long as deep. Brownish 

 above, yellowish below ; dorsal dusky, other fins pale. 



Hah. Eio Grande System ; E,ivers of Texas and Tamaulipas : 



R. Lampasas '^ and R. Salado ^ in Texas ; R. Conchos in Chihuahua '^ ; 

 R. San Juan in Nuevo Leon ^ "^ ; R. Conchos and R. Soto Marina in Tamau- 

 lipas 4. 



Here described from two specimens, 120 and 160 mm. in total length, from the 

 Rio Soto Marina (^Mccli). The species attains a length of 350 mm. 



2. Moxostoma austrinum. 



Myxostoma austriiia, Bean, Proc. U.S. Nat. j\lus. 1879, p. 302 '. 



Moxostoma austrinum, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 192". 



Myzosto'iaa austrinum, Meek, Publ. Columbian Mus., Zool. v. 190 1, p. 35 \ 



About 10 pharyngeal teeth on each side. Depth of body 4-^ in the length, Icugth of head 4^ to 4t. 

 Diameter of eye 5j to 5i in the length of head, length of snout 2i, intororbital width 2| to 2J. Snout 

 truncated anteriorly. Lips plicated; lower lip with a straight transverse posterior edge; width of 

 mouth g the width of head. 47 to 50 scales in a longitudinal series, 7 in a transverse series from ori'nn 

 of dorsal fin to lateral line, 6 from lateral line to base of ventral fin. Dorsal 12, tlie 2 anterior rays 

 simple ; origin nearer to tip of snout than to base of caudal ; free edge straight or slightly concave ; 

 longest ray a little longer than the base of the fin. Anal 8, with the 2 anterior rays simple, the fin, 

 w4icn laid back, extending nearly to the base of caudal. Pectoral a little shorter than the head 

 extending rather more than | of the distance from its base to the origin of the ventral, which is below 

 the middle of the dorsal. Caudal emarginate. Caudal peduncle 1^ as long as deep. Brownish above 

 yellowish below ; dorsal dusky, lower fins pale yellowish. 



Hah. Mexico, Rio Mezquital and Rio Lerma Systems : 



Durango ^ ; Aguas Calientes and Ataquiza in Jalisco ^ ; Salamanca in Guana- 

 juato ^ ; Lake Chapala ^ ; Morelia in Michoacan 1. 



Here described from two specimens from Aguas Calientes [Jordan), 130 and 150 mm. 

 in total length. The species grows to the same size as the preceding one. 



