221: iBUTIOXS TO NORTH AMERICAN ICHTHYOLOGY IV. 



anterior; premaxillaries protractile; fold of lower lip not crossing the 

 syniphysis; lower jaw trenchant, without horny covering ; no barbels. 

 Gill rakers short. IMiaryngcals strong. Teeth 3-3, of the Mylochihts 

 type, more or less cylindrical, with rounded grinding surfaces, posterior 

 more slender and siibconical. (*?>-,;. stump ; o<>, tooth.) 



352. S. sigiiifcr Uarm.m. 



Dorsal and ventral outlines similar. Eye large, longer than snout. 

 Mouth oblique, the maxillary not reaching front of eye. Lower jaw the 

 longer. Pectorals not reaching veutrals, the latter to anal. Brown; 

 silvery below ; a broad brown lateral band, bordered above by a nar- 

 row silvery line. Head 3; depth 3. D. 8; A. 8; scales G-35-L* ; 

 " teeth 3-3, stout, stump-like, with convex summits." Lago de Parras, 

 an isolated lagoon in Coahuila, Mexico. (Gorman,) 



(Carman, 1. c. 1)0.) 



98. UIYLOCIIILUS Agassiz. 



(Mylocleilus Agassiz, Amcr. Journ. Sci. Arts, 1855, 229: typo Mylocheilus lateraUt 

 Agussiz = Lcuciscus caurinu* Rich.) 



Body elongate, not elevated, little compressed. Ilead rather short, 

 conic, somewhat pointed. Mouth rather small, little oblique, the lower 

 jaw included; maxillary with small barbel at its end; upper jaw pro- 

 tractile. Scales moderate not closely imbricated. Lateral line de- 

 enrved. Dorsal fin beginning nearly opposite ventrals. Caudal fin with 

 the rudimentary rays little developed. Anal basis short. Intestinal 

 canal about as Ion- as body. Teeth L', ;">-f, '2, or 2, ."5-4, 2, two or three 

 of those in the main row molar, much enlarged, blunt and truncate 

 >ve. (A third deciduous row sometimes present, according to Girard, 

 in this -rims and in Mylopharodon; we have seen nothing of the kind.) 

 Si/.c lar--.-. (:>.>>).<>-, grinder; ^^."T, lip.) 



353. II. ranriiius (Richardson) <;nl. Columbia Chub. 



shorter than snout, ."5 in head; interorbital space broad, 

 convex. Month hoiixontal or neai'ly so, the maxillary not reaching the 

 front of the eye; suborhif :il hones wide; preorbital elongate. Color 

 dark aliov. : sides -ilvery, a dark lateral band; below this a pale 

 stripe; under which is a dark stripe which extends about to the vent; 

 fins plain; belly and pale stripe red in spring males. ETead4-|; depth 

 D.8; A Lee i:;-70-l<>; teeth 2, ">-5, 2. L. 12 inches. Streams 



