170 Bulletin 4j, United States National Museum. 



ee. Caudal long, deeply forked, its lobes pointed, longer tliiiii 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 Catosloiiiiis). 



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



Columbia basins. jordani, 27fi. 



ff. Scales in latiral lino about 70; lower lip more incised. 



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

 Nevada basin. ar.«opi:s, 277. 



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



ci.AUKi, 278. 

 271. PANTOSTEITS ARIZONJE, Gilbert, now species. 

 Head 4? ; deptli 4f . D. 12 ; A. 7. Scales 8-75-11 to 17 ; nnnsnally large 

 scales before dorsal. Body rather robust, the caudal jieduucle 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, li^ 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-i^ir in head ; caudal well forked, 1^- 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 basia. 



Pantoxteus arir.<m:f, GiLHERT, MS., Salt River, Tempe, Arizona. 



272. PANTOSTEUS GENEROSUS, (Girard). 

 (Mountain Sucker.) 

 Body moderately elongate, the depth 5 to 5j 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 with2. 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 baud. L. 8 

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

 Lake and southwest through the Sevier basiu and the desert. (Gencrosiis, 

 generous.) 



Caloslomusgeiierosiis,GlRAYiv, Proc. Ac. Nat. Sci. Phila., 1856, 174, Cottonwood Creek, Utah. 



(Type,No.25G.) 

 Minonms jarrovii. Cope, Proc. Am. Phil. Soc. Phila., 1874, 129-139, Prove River, Utah. (Type, 



No. 18008.) 

 Panlonleus generosux, .Jordan & Gilfiert; Synopsis, 123, 1883. 

 Mhomiia plalyrhymJtm, Cove, Proc. Am. Phil. Soc. Pliila., 1874, 134, Utah Lake at Prove. 



(Type,No.ir)7C3.) . 

 Panlonteusplalyrhiinchiis, JORDAN & GILBERT, Synopsis, 124, 1883. 



273. PANTOSTEUS PLEBEIUS, (Baird ct Girard). 

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

 Ventrals reaching nearly to vent. Scales moderate, scarcely crowded 

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



