PLECTOSPONDYL1 CYPE1NIDAE C. BIGUTTATUS. 



651 



width. Width of head behind one-half the length. Length of head enter- 

 ing 4.2 times total to base of caudal ; greatest depth of body nearly six 

 times in the same. Total length, O m .OS2 ; length to basis of caudal fin, 

 (T.GO ; to basis of dorsal fin, O m .033. 



Color silvery, with a broad, silvery, lateral band, which has a leaden 

 superior margin ; a dusky dorsal band. 



The dentition of this species, like that of the Gila fegregia, is frequently 

 anomalous ; normally 4.1-1.4, it is sometimes on one side 4.3.2-, 1.4.1-, and 

 2.2.2. It seems to be nearly allied to the eastern A. jaculus. 



CERATICHTHYS, Bd. 



CEEATICHTHYS BIGUTTATUS, Kirt. 



PLATE XXIX, FIG. 1. 



Semotilus biguttatus, KIET., Bost. Jour. Nat. Hist., iii, 1840, 3, 44. 



Ceratickthys biguttatus, Gm., P. E. E. Eep., Fishes, x, 1859, 253. COPE, CyprinidaB 



of Penna., Oct., 1SGG, 3GG, tab. xi, f. 5. Id., Proc. Am. Phil. Soc. Phila., 



1874, 136. Id., Plagop. & Ichtby. Utah, 1874, 10. 

 Ceratichtliys biguttatus var. cyclotis, COPE, Proc. Acad. Nat. Sci. Phila., 1SG4, 278. 



As already noted, tin's common eastern species was unexpectedly discov- 

 ered by Dr. H. C. Yarrow at Harmony, in Southern Utah, in 1872. Up to 

 this time, the Smoky Hill River was the western limit of its distribution. 



CEEATICHTHYS PHYSIGNATHUS, Cope, sp. nov. 



A large-scaled species, with slender body and wide, depressed head. 

 The dorsal line is but little arched, and the profile of the muzzle descends 

 steeply to the lip. The upper lip extends beyond the lower, and the max- 

 illary bone reaches the line of the anterior border of the orbit. The beards 

 are well developed, and the teeth number 4.2-2.4. Eye 4.6 in length of 



