THE SALMON FAMILY. 63 
America, —a remarkable fact in geographical dis- 
tribution, perhaps explained only on the hypoth- 
esis of the comparatively recent and Eurasiatic 
origin of the group, which, we may suppose, has 
not yet had opportunity to extend its range across 
the plains, unsuitable for salmon life, which separate 
the upper Missouri from the Great Lakes. 
The Salmon (Salmo salar) is the only black- 
spotted salmonoid found in American waters tribu- 
tary to the Atlantic. In Europe, where other 
species similarly colored occur, the species may 
be best distinguished by the fact that the teeth on 
the shaft of the vomer mostly disappear with age. 
From the only other species positively known 
(Salmo trutta) which shares this character, the 
true salmon may be distinguished by the presence 
of but eleven scales between the adipose fin and the 
lateral line, while Sa/mo trutta has about fourteen. 
The scales are comparatively large in the salmon, 
there being about one hundred and twenty-five in 
the lateral line, The caudal fin, which is forked 
in the young, becomes, as in other species of sal- 
mon, more or less truncate with age. The pyloric 
coeeca are fifty to sixty in number. 
The following account of the coloration of 
the salmon is from Dr. Day’s “Fishes of Great 
Britain: — 
“Color in adults superiorly of a steel blue, becoming 
lighter on the sides and beneath. Mostly a few rounded 
or x-shaped spots scattered above the lateral line and 
upper half of the head, being more numerous in the 
female than in the male. Dorsal, caudal, and pectoral 
fins dusky; ventrals and anal white, the former grayish 
