FAMILY X. SALMONID^;. 95 



its length 3 to 3 in head; origin of dorsal fin midway between tip 

 of snout and tip of last anal ray ; last ray of dorsal 3 in body ; pectoral 

 1^3 in head, reaching base of ventrals; ventrals' 23^; base of anal fin 

 equaling length of head; scutes well developed, 15 or 16 + 9; scales 

 large, thin, deciduous; caudal fin forked; least depth of caudal pedun- 

 cle 2>^ in head. 



Color brownish above, light silvery below, the opercles and ad- 

 joining region with considerable yellowish; a black humeral spot; fins 

 all plain. Length about 6 inches. 



Mr. C. Tate Regan, of the British Museum, has kindly reexamined 

 the types of Chatoessus mexicanus Giinther, and he informs me that 

 Signalosa atchajalayce Evermann & Kendall is the same species. 



Family X. Sal HI on Ida". 



THE SALMON FAMILY. 



Body elongate, covered with cycloid scales; head naked; mouth 

 terminal, large or small, the maxillary forming its lateral margin; 

 maxillary with a supplemental bone; premaxillaries not protractile; 

 teeth various, sometimes wanting; pseudobranchiae present; gill 

 membranes not connected, free from the isthmus; branchiostegals 

 10 to 20; no barbels; dorsal fin small, placed near the middle of the 

 body, its rays 9 to 15; adipose fin present; caudal fin forked; lateral 

 line present; abdomen rounded in outline; air bladder large; stomach 

 siphonal; pyloric cceca numerous; ova large, falling into cavity of the 

 body before exclusion. 



The fishes which belong to this family are confined to the northern 

 regions, one species ranging as far south as Durango. 



'Subfamily Salmoninae. 

 4:2. Salmo (Artedi) Linnaeus. 



SALMON AND TROUT. 

 Salmo (Artedi, Genera Piscium) Linnaeus, Syst. Nat., Ed. x, 302, 



1758. (Type, Salmo salar Linnaeus.) 



Body elongate, somewhat compressed; mouth large; jaws, pala- 

 tines, and tongue toothed; vomer flat, its shaft not depressed, a few v 

 teeth on chevron of the vomer, behind which is a somewhat irregular 

 single or double series of teeth (in migratory forms deciduous with 

 age); scales small, more than 100 in the lateral series; dorsal and 

 anal fins short, of 10 to 12* rays each; sides and median fins black 

 spotted. 



The species of this genus are confined to the colder portions of the 

 northern hemisphere. Of the three species on the Atlantic side of 



