474 GEOLOGICAL SUEVEY OF THE TEEEITOEIES. 



attaining the point opposite to tile origin of the ventrnl fins. Length 

 of head, 4.33 ; depth of body five times into length without caudal fin ; 

 diameter of eye four times in head ; once in muzzle, 1.3 times in 

 interorhital width. Fin radii, D. I. 8 ; A. I. 7. Eays of pectoral 

 thickened, not. reaching ventral; ventral reaching anal. Length, 24 

 lines ; teeth, 4.2-1.4, somewhat hooked. 



Color silver-gray, with a broad dark lateral band, which is darker 

 spotted ; back and sides of thorax flark shaded ; top of head dark. 



Numerous specimens from Fort Hall, Idaho, collection No. 3, 



Hybopsis bivittatus, Cope, sp. nov. 



Muzzle narrow, very obtusely descending, not projecting; mouth 

 horizontal, end of maxilla reaching the line of the orbit. Orbit 

 four times in length of head, 1.5 times in the rather flat inter- 

 orbital width. Length of head, 4.66 times ; depth of body four 

 times in length minus caudal fin. Dorsal region arched; basis 

 of dorsal fin descending posteriorly, and originating very little 

 behind origin of ventrals. Pectorals only reaching half-way to ventrals; 

 latter about half-way to anal. Eadii, D. I. 8; A. I. 7. Teeth, 4.2-2.4, 

 with grinding surface. Scales, 12-53-11. Lateral line complete. Dor- 

 sal fin nearer muzzle than origin; caudal fin midway between former 

 and notch of latter. Length, 3 inches. 



Color silvery; the scales blackish punctulate; dorsal region blackish; 

 a dark baud from epiclavicular region to basis of caudal fin ; another 

 from end muzzle, across operculum, to basis of anal. 



From Warm Springs, Utah ; Campbell Carrington, collector. Collec- 

 tion No. 10. 



It is interesting to note that in the distribution of color, especially in 

 the two lateral bands, this species is identical with Frotoporus domninus, 

 Tigoma rMnichthyoicles, and Apocope carringto7vii, a well-marked case of 

 mimetic analogy. Another case of this kind is exhibited by two species 

 of eels of different genera from Costa Eica. The species are undescribed. 



MuE^NA AQU^DiJLCis, Cope, sp. nov. 



Branchial fissure small ; posterior nostril not tubular, situated half- 

 way between eye and anterior nostril. Eye contained nearly twice in 

 the muzzle. Maxillary teeth in two rows, ethmoids in a single one. 

 Former, 4 long in the inner, 17 in the outer row, counting from the front 

 margin of the orbit. Vomerine teeth well developed ; deutaries in two 

 rows. 



Form stout; dorsal fin extending two-thirds the total length, the anal 

 2.33 times in the length. Color brownish-black, with ratlier distant 

 yellow spots, which are accompanied by a darker shade on same side, and 

 which become confluent into yellow marblings on the gular and i^ectoral 

 regions. 



From the Eio Grande, near the city of San Jose, Costa Eica, Central 

 America. 



PCECILOPHIS NOCTUENUS, Cope, Sp. tlOV. 



Branchial fissure small; posterior nostril just above the orbit at the 

 anterior margin. Muzzle rather obtuse, twice as long as the small eye. 

 Maxillary teeth in a single row ; the vomerines obtuse, continued in line 

 to the ethmoids. Latter in three rows, with interspaces. Deutaries one- 

 rowed. Form moderately stout; dorsal fin extending nearly to nape. 

 Anal fin a little over one-third total length. 



