SALMO. — DOEOSOMA. 177 



Hah. Streams of the Eocky Mountains and Sierra Nevada, from Kamchatka and 

 Alaska to California and Dnraneo 



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 Duranso. 



A second form, S. phuriticus. 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. CLUPEID^. 



A large and widely distributed marine family ; several species are anadromous, and 

 some are permanently fluviatile. 



The Clupeidse 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 1. Dorosoma. 



Maxillary bearing two supramaxillaries 2. Signalosa. 



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 3. Lycengraulis. 



Teeth in the jaws very small or absent 4. Anchovia. 



1. DOROSOMA, Rafin., 1829. 



Chatoesms (Cuv.), Gunth. 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. 



Synoptsis of the Mexican and Central- American Species. 



74 to 78 scales in a longitudinal series ; anal of 26 to 30 rays 1. chavesi. 



69 to 73 scales in a longitudinal series ; anal of 36 to 38 rays 2. anale. 



56 to 60 scales in a longitudinal series j anal of 30 to 34 rays . 3. exile. 



40 to 45 scales in a longitudinal series ; anal of 21 to 24 rays 4. peteneme. 



1. Dorosoma chavesi. 



Dorosoma chavesi, Meek, Publ. Columbian Mus., Zool. vii. 1907, p. 112 '. 

 Eab. NiCAEAGUA, Lakes Managua and Nicaragua ^. 



Total length 210 mm. 

 BIOL. CBNTK.-AMER., Pisces, February 1908. 2 A 



