SALMO.—DOROSOMA. 177 
Hab, Streams of the Rocky Mountains and Sierra Nevada, from Kamchatka and 
Alaska to California and Durango. 
This species embraces a number of local forms, including S. spilurus, Cope (Jord. & 
Everm. t.c. p. 495, fig. 210), which inhabits the upper Rio Grande and extends 
southwards into Chihuahua and Durango. 
A second form, 8. pleuriticus, Cope (Jord. & Everm. t. c. p. 496, fig. 211), is found 
in the Colorado River, and is probably the trout reported by Meek as abundant in the 
Rio Yaqui in Sonora. 
Fam. 2. CLUPEIDA. 
A large and widely distributed marine family; several species are anadromous, and 
some are permanently fluviatile. 
The Clupeide may be distinguished from other soft-rayed fishes of the fresh waters 
of Mexico and Central America by the compressed body, covered with thin cycloid 
scales, the naked head, the feeble dentition, and the absence of a lateral line. 
Synopsis of the Genera represented in the fresh waters of Mexico 
and Central America. 
I. Abdomen compressed to a serrated edge ; mouth small or moderate; last dorsal ray elongate. 
Maxillary bearing one supramaxillary . . . . . . . . 4. « , « « « J. Dorosoma. 
Maxillary bearing two supramaxillaries . . . . . . . . . +. . . 2 Signanosa. 
II. Abdomen not serrated ; mouth large, the maxillary extending back far behind the eye; last 
dorsal ray not elongate. 
Teeth in the jaws evident, some more or less enlarged . . . . . . . . 8. LiycENGRAULIS. 
Teeth in the jaws very smallor absent . . . ...... . =. . . 4 ANCHoVIA. 
1. DOROSOMA, Rafin., 1829. 
Chatoessus (Cuv.), Giinth. Cat. Fish. vii. p. 406 (1868). 
Dorosoma, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 415. 
Five species from the Atlantic coasts and rivers of America. 
Synopsis of the Mexican and Central-American Species. 
74 to 78 scales in a longitudinal series; anal of 26 to 80 rays . . . . . . . LL chavesi. 
69 to 73 scales in a longitudinal series; anal of 86 to 388 rays  . . . . . . . 2, anale. 
56 to 60 scales in a longitudinal series; anal of 30 to 34 rays . . . . . . . 38. exile. 
40 to 45 scales in a longitudinal series; anal of 21 to24rays . . . . . . . 4& petenense. 
1. Dorosoma chavesi. 
Dorosoma chavesi, Meek, Publ. Columbian Mus., Zool. vii. 1907, p. 112 i 
Hab. Nicaragua, Lakes Managua and Nicaragua’. 
Total length 210 mm. 
BIOL. CENTR.-AMER., Pisces, February 1908. 2A 
