212 Bulletin 47, United States National Museum. 



base of caudal; upper fins dusky, unmarked. Length 6| inches. Cen- 

 tral Mexico, in streams tributary to Rio de Lerma ; our specimens col- 

 lected by Mr. Woolman, at Salamanca. Very close to A. tinceUa, but 

 probably distinct. (Named for Professor Alfredo Duges, who collected 

 the types.) 



Algansea dugesi, BEAN, Proc. U. S. Nat. Mus., 1892, 283, Guanajuato, Lake Yuriria. (Type, 

 Nos. 41818 and 43764.) 



339. ALGANSEA SALL.EI (Giinther). 



Head 4 ; depth 3 j eye 5. D. 7; A. 6. Lateral line 54 j teeth 4-4, long, 

 curved, with grinding surface. Caudal peduncle not quite twice as iong 

 as deep. No barbels. Snout obtusely conical, longer than the eye. 

 Upper jaw slightly overlapping the lower. Maxillary not extending to 

 the eye. Dorsal immediately behind ventrals. Fins short. Intestinal 

 canal with few convolutions. Brownish, green above, minutely dotted 

 with black along the sides. Length Scinches. Streams of central Mexico. 

 (Giinther.) (Named for M. Salle, a collector in Mexico, who obtained 

 the types.) 



Ceratichthys sallsel, GUNTHER, Cat.,vn, 484, 1868, Cuernavaca, Mexico. 

 Zophendum awtrale,* JORDAN, Proc. U. S. Nat. Mus., 1870, 300, Lake Tupataro. (Type, Nos. 



23130 and 23131. Coll. Prof. A. Duges.) JORDAN & GILBERT, Synopsis, 154, 1883. 

 Hudsonius salleei, JORDAN, Proc. U. S. Nat. Mus., 1879, 226. 

 Cliola eallsei, JORDAN & GILBERT, Synopsis, 164, 1883. 



107. HYBOGNATHUS, Agassiz 



Hybognaihus, AGASSIZ, Amer. Journ. Sci. Arts, 1855, 223, (nuchalis). 

 Dionda, GIRARD, Proc. Ac. Nat. Sci. Phila., 1856, 177, (episcopa). 

 Algoma, GIRARD, I. c., 180, (amara). 



Body elongate, somewhat compressed. Mouth horizontal, the jaws 

 normal, sharp-edged; lower jaw with a slight, hard protuberance in front; 

 no barbel; upper jaw protractile. Teeth 4-4, cul triform, Avith oblique 

 grinding surface and little if any hook. Alimentary canal elongate, 3 to 

 10 times the length of the body. Peritoneum black. Scales large ; lateral 

 line continuous. Dorsal inserted before- ventrals. Anal basis short. 

 Size moderate. Sexual changes very slight, no red or black pigment dis- 

 tinguishing the males in spring. Species numerous ; mostly southwestern, 

 and not well known. (v(36s , gibbous ; yvdOos, jaw.) 



HYBOGNATHUS : 

 a. Teeth comparatively long and scarcely hooked ; silvery species, usually more than 3% 



inches in length when adult ; scales about 38. 

 b. Suborbitals broad, the anterior not more than twice as long as deep. 



c. Mouth narrow, its cleft not reaching nearly to eye ; lower jaw shorter than upper, 



obtuse at tip. NUCHALIS, 340. 



cc. Mouth wide, its cleft about reaching eye ; jaws subequal, the lower acutish at tip. 



ARGYRITIS, oil. 



bb. Suborbitals narrow, the anterior about 3 times as long as deep ; mouth rather small. 



ii AY i, 342. 



* Algansea australis, (Jordan). Head 4; depth 4%. D. 8; A. 7. Scales 10-5G-8. Teeth 4-4. 

 Body rather elongate, formed as in Camposloma anomalum, somewhat compressed, the back 

 somewhat elevated and rounded anteriorly. Head rather large, slightly depressed above. Mouth 

 moderate, low ; the lower jaw slightly included ; the premaxillary below the level of the eye; 

 maxillary just reaching the front of the eye. Lower jaw thin-edged, with a slight symphyseal 

 knob. Eye small, 6 iu head. Scales small. Lateral line complete, decurved. Dorsal slightly 

 behind ventrals. Dusky bluish above ; everywhere with dark points ; a black spot at base of 

 caudal. Length 7 inches. Lake Tupataro, Guanajuato, Mexico, a tributary of Rio Lerma, west 

 of the Sierra Madre. Doubtless the adult of Algansea sallsei. 



