Adviuice Notes from "A (iuiilf to Ihc Sliidv oi' 1m<1ic^. " I'.v (■(Hirtcsv <p|' lU-iii-v Hull <\: Co. 



PACIFIC SPECIES OF SALMON AND TROUT. 



By DAVID STARR JORDAN, President of Lclaiid Stanford .Tuiiiur Universitv 



salmonid;e. 



The Salmon Family. — The series or suborder Salmonoidea, or allies 

 of the salmon and trout, are characterized as a whole by the presence 

 of the adipose fin, a structure also retained in Characius and catfishes, 

 which have no evident affinity with the trout, and in the lantern- 

 fishes, lizard-fishes, and trout-perches, in which the affinity is very 

 remote. Probably these groups all have a common descent from some 

 primitive fish having an adipose fin, or at least a fleshy fold on 

 the back. 



Of all the families of fishes, the one most interesting from almost 

 every point of view is that of the Salmoniche, the salmon family. As 

 now restricted, it is not one of the largest families, as it comprises less 

 than a hundred species; but in beauty, activity, gaminess, quality as 

 food, and even in size of individuals, different members of the group 

 stand easily with the first among fishes. The following are the chief 

 external characteristics which are common to the members of the 

 family : 



Body oblong or moderately elongate, covered with cycloid scales of 

 varying size. Head naked. Mouth terminal or somewhat inferior, 

 varying considerably among the different species, those having the 

 mouth largest usually having also the strongest teeth. Maxillary pro- 

 vided with a supplemental bone, and forming the lateral margin of 

 the upper jaw. Pseudobranchise present. Gill-rakers varying with 

 the species. Opercula complete. No barbels. Dorsal fin of moderate 

 length, placed near the middle of the length of the body. Adipose fin 

 well developed. Caudal fin forked. Anal fin moderate or rather 

 long. Ventral fins nearly median in position. Pectoral fins inserted 

 low. Lateral line present. Outline of belly rounded. Vertebra^ in 

 large number, usually about sixty. 



The stomach in all the SalmonidR' is siphonal, and at the pylorus 

 are many (15 to 200) comparatively large pyloric ca>ca. The air- 

 bladder is large. The eggs are usually much larger than in fishes gen- 

 erally, and the ovaries are without special duct, the ova falling into 



