876 



FISHES — SALMONID^. 



Description. — Body closely compressed, becomiag deep in the adalt; eye moderate, 

 smaller than in other species, about 3^ in head, the maxillary reaching to beyond its 

 middle; back less arched, snout blnnter and more elevated than in B tergism, month 

 larger and more obliqne ; pectorals longer and ventrals shorter than in H. iergiaus ; belly 

 carinated both before and behind ventrals; bluish, sides silvery, with golden luster; 

 head 4 3-4; depth 3i; D. 9; A. 3i; scales 6-56-7. 



Habitat, Ohio River to the Saskatchawan ; common northward. 



Diagnosis. — From Hyodon tergisus, this species may be known by its 

 short dorsal, of but nine developed rays, and by the carination of the 

 whole ventral edge. 



Sabits. — Nothing distinctive is known of the habits of this species. 

 Originally described by Rafinesque from the Falls of the Ohio, its occur- 

 rence southward has been overlooked until very lately. In 1836 it was 

 found in the Saskatchawan River by Sir John Richardson, and later by 

 Dr. Coues in the Upper Missouri. In 1880 the writer obtained numer- 

 ous specimens at the Falls of the Ohio, and was thus enabled to recog- 

 nize the Amphiodon alosoides of Rafinesque. The species will doubtless 

 be found in all the larger rivers of the Northwest. A third species, 

 Hyodon selenops, Jordan and Bean, occurs in the rivers of the Southern 

 States, but has not yet been seen in Ohio. 



FAMILY XIII. SALMONID^. THE SALMONS. 



Body oblong or elongate, covered with cycloid scales ; head naked ; month terminal, 

 varying moch in size and form ; max illary forming the lateral margin of the upper j 4W, 

 provided with a supplemental bone, premaxillaries not protractile ; teeth various, some- 

 times wanting ; gills four, a slit behind the fourth ; pseudobranchiee pieseat, but often 

 small or rndimentary ; gill-rakers moderate ; gill-membranes not connected, free from 

 the isthmus ; branchiostegals 6-30 ; no barbels ; dorsal usually median, not greatly 

 elongate ; adipose fin present ; candal fin forked ; anal fin moderate or rather long ; 

 ventrals moderate, nearly median ; pectorals placed low ; lateral line present ; abdomen 

 rounded ; air-bladder large ; stomach coecal or siphonal, the pyloric coeca few or many, 

 sometimes obsolete ; ova generally large, falling into the cavity of the abdomen before 

 exclasion ; genera about 20 ; species 125, a large and varied family. Its members in- 

 habit chiefly the fresh waters of northern regions, many of them being anadromous, run- 

 ning up from the sea to spawn in the rivers. One genus, Metropinna, is fonnd in New 

 Zealand, and the species of Microstoma, Argentina, and Silus are mostly deep sea fishes. 

 In economic importance this family ranks among the very first, and the Salmon and 

 Trout in all northern regions are the choicest prize of the angler. 



Analysis of Genera of Salmonid.*:. 



o Pyloric coeca many ; stomach siphonal. 

 i. Jaws toothless or nearly so ; scales large. (Coregonince.) 



0. Maxillary short and broad Cokegonus. 49. 



bb. Jaws with distinct teeth ; scales mostly small. (Salmonince.) 



