GEOLOGICAL SURVEY OF THE TERRITORIES. 441 



than usually stout symphysis. The form of the lower lip and anterior 

 position of the dorsal fin separate it from Photogenis. As the dorsal fin is 

 immediately above the ventrals in Exoglossum maxillingua, and as Gi- 

 rard represents its position to be the same as in Sarcidium in his Ex. mi- 

 rabile from Texas, (United States Pacific Railroad Report, X, plate LVI,) 

 I suspect that the latter will be found to be a species of Sarcidium. 



Char, specificus : General proportions medium, the back nearly 

 straight; the caudal region stout ; the head rather small, with long and 

 prominent but obtuse muzzle ; mouth entirely inferior, the end of the 

 maxillary about reaching the line of the anterior nares ; length of 

 head into total, without caudal fin, four times ; depth at dorsal into 

 same, 4.75 times ; origin of dorsal nearer end of muzzle than basis of 

 caudal fin ; eye 4.2 times in length of head ; 1.6 times in muzzle, nearly 

 equal interorbital width ; vertex nearly plane ; profile slightly convex 

 to a point opposite front nares ; here it descends into a deep trans- 

 verse notch, which is caused by a failure of the spines of the pre- 

 maxillary to reach the nasal bones ; preorbital bone long and narrow ; 

 lateral line nearly straight ; scales 6-44-5 ; fin radii, D. 1.8; A. I. 7 ; 

 Y. 8 ; pectorals not reaching ventrals ; ventrals reaching vent, which is 

 a little in advance of the anal fin ; length, M. .0545 ; depth at last anal ray, 

 .006. 



Color, olivaceous, (reddish in alcohol,) with a straight silver lateral 

 band ; this terminates in a strong black spot at the middle of the base of 

 the caudal fin. No dark dorsal band. 



This peculiar little fish was taken in the Missouri River, near St. 

 Joseph, Missouri. (Mus. Chicago Acad. Sciences.) 



Gilaelegans, Baird andGirard, Sitgreaves's Expedition. Zuniand 

 Colorado, 1853, 149, Fishes, PL II. — Fort Bridger, two specimens ; Forks 

 of Green River, two specimens. 



Gila grahamii, Baird and Girard ; United States Mexican Boundary 

 Survey Report, Fishes, p. 61, PL XXIV, figs„ 7-12. — Fort Bridger, one 

 specimen ; Henry's Fork, one specimen. 



Gila gracilis, Baird and Girard ; Sitgreaves's Report, 1853, 151, PI. 

 III. — Fort Bridger, one specimen; Henry's Fork, two specimens; Forks 

 of Green River, five specimens. 



GrILA NACREA, (COPE ;) Sp. n0V. 



Allied to G. grahamit, Baird and Girard. Radii, ~D, 2. 9 ; C. 6. 10. 11. 6 ; 

 A. 2. 10; Y. 9 ; P. 14. Scales, 21—13. Length of head four times in 

 total to basis of median caudal radii ; depth at dorsal fin four and three- 

 fifths times in the same. Ventrals originating in advance of dorsal fin, 

 not reached by the pectorals. Least depth of caudal peduncle 2.5 times 

 into the depth at ventral fins. Profile and interorbital region gently 

 convex; width of latter 3.1 times in length of head; diameter of eye 

 five times in length of head, and 1.25 times in length of muzzle, end of 

 maxillary not reaching line of orbit. Teeth 4.2-2.5. Total length, M. 

 0.136 ; depth of head at orbit, .015 ; width of head behind, .0125 ; length 

 of head, .028; depth caudal peduncle, .007. Color, silver- white; back 

 narrowly dark shaded ; pectoral fin, pink. From the fork of the Green 

 River near Fort Bridger, Wyoming Territory; collected by Cam. 

 Carrington, of Dr. F. V. Hayden's expedition. 



This species is near the G. gralmmii in number of anal rays and gen- 

 eral proportions, but has a less depressed form of cranium and much 

 larger eye. The head is more like that of Ceratichthys and ordinary 

 Cyprinidw. 



