30 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. V. 



Color silvery plumbeous on upper half of body, lower white ; middle 

 of each scale more silvery than the margin, forming indistinct silvery 

 lateral stripes along the rows of scales. 



This species is easily distinguished by being more slender than any 

 other member of the genus and having thick papillose lips like the 

 species of Catostomus. One large (type) and one small (i l / inches) 

 specimen were taken at Valles. 



Subfamily Catostominee. 



1O. Pantosteus Cope. 



MOUNTAIN SUCKERS. 



Pantosteus Cope, Lieut. Wheeler's Expl. W., looth Mer., v., 673, 

 1876. (Type, Minomus platyrhynchus Cope.) 



Body rather elongate, not much compressed; head rather small; 

 suborbital bones narrow; bones of the head rather thick; the parietal 

 bones in the adult more or less uniting, partly or wholly obliterating 

 the fontanelle; mouth large, entirely inferior; each jaw with a devel- 

 oped cartilaginous sheath; upper lip broad, papillose, with a rather 

 broad free margin, and two or more series of tubercles; lower lip largely 

 developed, the broad deep margin deeply incised behind; pharyngeal 

 bones and teeth essentially as in Catostomus; isthmus broad; scales 

 small, 80 to over too in lateral series; lateral line well developed, nearly 

 straight; fins rather small; caudal short, emarginate; air bladder in 

 two parts. 



25. Pantosteus plebeius (Baird & Girard). 



Catostomus plebeius Baird & Girard, Proc. Acad. Nat. Sci. Phila., 



1854, 28; Rio Mimbres, a tributary of Lago de Guzman. 

 Minomus plebeius Girard, Proc. Acad. Nat. Sci. Phila., 1856, 173; 



Rio Janos, tributary of Lago de Guzman: Girard, Mex. Bd. 



Sur.,38,pl. xxn, figs. 1-4, 1858; Rio Mimbres. 

 Catostomus guzmaniensis Girard, Proc. Acad. Nat. Sci. Phila., 1856, 



173; Rio Janos, tributary of Lago de Guzman. 

 Acomus guzmaniensis Girard, Mex. Bd. Sur., 39, pi. xxm, figs. 



i-io, 1858; Rio Janos, tributary of Lago de Guzman. 

 Catostomus nebuliferus Garman, Bull. Mus. Comp. Zool., 1881, 



vin, 89; Rio Nazas, Coahuila. 

 Pantosteus plebeius Jordan & Evermann, Bull. 47, U. S. Nat. Mus., 



1896, 171: Bean, Bull. Amer. Mus. Nat. Hist., 1898, 167; San 



Diego, Chihuahua: Evermann & Goldsborough, Bull. U. S. Fish 



Comm., 1902, 146; Rio Piedras, Colonia Garcia and Rio Casas 



Grandes, Casas Grandes, Chihuahua: Meek, Field Col. Mus. Pub. 



65, 1902, 75; Colonia Juarez; Ahumada; San Andres; Minaca. 



