170 Bulletin 47, United States National Museum. 



ee. Caudal long, deeply forked, its lobes pointed, longer than head. Head short, 



5 in length. Coahuila basin. GUZMANIENSIS, 275. 



aa. Fontanelle remaining partly open in the adult; scales small, crowded anteriorly; dorsal 



short (transition species, approaching Catostomus). 



f. Scales in lateral line 90 to 100 ; head short, 4% to 5 in length. Upper Missouri and 

 Columbia basins. JORDANI, 276. 



ff. Scales in lateral line about 70; lower lip more incised. 



g. Scales before dorsal 42, the scales of the body being much crowded forward. 

 Nevada basin. AR^OPUS, 277. 



gg. Scales before dorsal 23, the scales of body little crowded forward. Gila basin. 



CLARKI, 278. 



271. PANTOSTEUS ARIZONJE, Gilbert, new species. 



Head 4f ; depth 4f. D. 12 ; A. 7. Scales 8-75-11 to 17 ; unusually large 

 scales before dorsal. Body rather robust, the caudal peduncle stoutish, 

 compressed. Head shortish, unusually broad and flat, the interorbital 

 very wide, flattened or even slightly concave, the orbital rim being some- 

 what raised; eye moderate, posterior, the snout very long, considerably 

 longer than rest of head ; eye 3 in snout, If in postorbital part of head, 

 5 in head ; mouth very wide, with wide papillose lips and well-developed 

 cartilaginous sheath to the jaws; fontanelle obliterated, the bone above 

 it very thin; isthmus broad. Fins all comparatively large, the pectoral 

 l^o in head ; caudal well forked, In,- in head, with numerous basal rudi- 

 mentary rays; edge of dorsal straight. Scales peculiar, those on back 

 very large, those along lateral line moderate, those on belly very small, 

 becoming minute below ; scales posteriorly along lateral line much larger 

 than anteriorly. Dark brown above, pale below. L. 9 inches. Gila basin. 



Panlosteus arizonie, GILBERT, MS., Salt River, Tempe, Arizona. 



272. PANTOSTEUS GENEROSUS, (Girard). 



(MOUNTAIN SUCKER.) 



Body moderately elongate, the depth 5 to 5f in length. Head short 

 and small, 4|- to 5 in length. Dorsal rays 9 (rarely 10); ventral rays 10 

 (rarely 9); scales 15-81-14. Lower lip full, with 4 or 5 rows of tuber- 

 cles; upper with 2. Isthmus very broad. Head with conspicuous mucous 

 tubes. Lower fins large. Light brown above, with dusky spots and 

 clouds ; males with the chin and fins red, and a crimson lateral band. L. 8 

 inches. Great Basin of Utah ; very abundant in streams about Great Salt 

 Lake and southwest through the Sevier basin and the desert. (Generosus, 

 generous.) 



Catostomus geiwrosus, GIRARD, Proc. Ac. Nat. Sci. Phila., 1856, 174, Cottonwood Creek, Utah. 



(Type, No. 256.) 

 Minomus jarrovii, COPE, Proc. Am. Phil. Soc. Phila., 1874, 129-139, Provo River, Utah . (Type, 



No. 18008.) 



Panlosteus generosus, JORDAN & GILBERT; Synopsis, 123, 1883. 

 Mhomm platyrhynchm, COPE, Proc. Am. Phil. Soc. Phila., 1874, 134, Utah Lake at Provo. 



(Type, No. 15763.) 

 Panlosteus pMyrhynchus, JORDAN & GILBERT, Synopsis, 124, 1883. 



273. PANTOSTEUS PLEBEIUS, (Baird & Girard). 



Head comparatively large, 4| to 4f- in length; depth 4f; eye 5 in head. 

 Ventrals reaching nearly to vent. Scales moderate, scarcely crowded 

 anteriorly, 80 in the lateral line, 25 to 30 in a cross series. Body rather 



