44o AMERICAN FISHES. 



THE SALMONIDiE IN GENERAL. 



TN Europe there is but one Salmon, but in this country they are many, 

 and in a book on American Fishes all must needs be mentioned. Since 

 the characters by which they are separated are rather minute, it will be 

 necessary to employ the technical language of ichthyology. 



The family Salmonirfce includes not only the Salmons and Trouts, but 

 also the graylings, smelts, whitefishes, capelins, oulachans and certain 

 other less familiar forms. The most prominent characteristic of the fishes 

 of this group is the little fleshy appendage on the posterior part of the 

 back, known as the soft, or adipose dorsal. This is found in many fishes 

 belonging not to the Salmonidce, but to allied groups, but none of these 

 inhabit our coasts or inland waters, except the Catfishes, which are not 

 likely to be mistaken for members of the salmon tribe. 



The following table, prepared by Dr. Bean, will enable any one to de- 

 termine at once to which genus any salmonoid fish belongs. 



THE GENERA OF SALMONIM:. 



[Key prepared by Dr. T. H. Bean.] 



A. Pyloric coeca many ; stomach siphonal. 



a. Dentition strong and complete ; conical teeth in jaws, vomer, and palatines ; scales many more than 

 ioo ; largely anadromous. 

 b. Anal rays 9 to n. 

 c. Vomer flat, its toothed surface plane; teeth on its shaft in pairs or in a zigzag row ; species black- 

 spotted. Subgenus Salmo. (The Sea Salmon.) 

 d. Sea-salmon, anadromous. 



dd. River-salmon, not anadromous. Subgenus Fakio. (The Salmon Trouts.) 



cc. Vomer boat shaped. 



e. Vomer with a raised crest, head and crest both toothed ; species gray-spotted. 



Ckistivomer. (The Lake Trouts.) 



ee. Vomer without raised crest, its shaft strongly depressed ; teeth on chevron only; 



species red spotted. Salvelinus. (The Brook Trouts or Charrs. ) 



bb. Anal rays 14 to 17. Oncorhvnchus. (The Pacific Salmons.) 



aa. Jaws toothless, or dentition feeble or incomplete ; scales little exceeding 100 ; not anadromous. 



f. Dorsal fin long and high, of about 20 rays. Thymallus. (The Graylings.) 



ff. Dorsal fin not elevated, rays about 10 to 13. 



g. Mouth small ; jaws toothless, or with a tew weak teeth. Coregonus. (The Lake White-fishes.) 



gg. Mouth large; vomer, palatines and tongue with bands of minute villiform teeth. 



Stenodus. (The Inconnu.) 

 AA. Pyloric caeca few or none ; stomach coecal 



h. Branchiostegals to 8 ; body compressed. 



i. Mouth large; ventrals in front of middle of dorsal. 



k. Pectoral rays 16 to 20 : scales very small : males with strong lateral ridges covered by modi- 

 fied scales. Mallotus. (The Capelins.) 

 kk. Pectoral rays 10 to 1.7 ; scales larger, similar in both sexes. 

 d. Teeth feeble, especially on tongue, scales small, adherent. 



Thaleichthys. (The Oulachans.) 

 dd. Teeth stronger, lingual teeth enlarged ; scales moderate, deciduous. Osmerus. (The Smelts.) 

 /. • Mouth moderate or small ; ventrals under or behind middle of dorsal. 

 //. Jaws with minute teeth; maxillary reaching past front of eye. Hypomesus. (The Surf-Smelts.) 



