THE SALMON FAMILY. 67 
the hypothesis of recent adaptation of the sal- 
mon to lake-life. We have, therefore, on our 
Atlantic coast but one species of salmon, Salmo 
salar. Dr. Francis Day, who has very thoroughly 
studied these fishes, takes, in his memoir on ‘ The 
Fishes of Great Britain and Ireland,” and in other 
papers, a similar view in regard to the European 
species. Omitting the species with permanent 
teeth on the shaft of the vomer (sub-genus Sa/ar), 
he finds among the salmon proper only two 
species, Salmo salar and Salmo trutta. The latter 
species, the sea-trout or salmon-trout of England, 
is similar to the salmon in many respects, but has 
rather smaller scales, there being fourteen in an 
oblique series between the adipose fin and the 
lateral line. It is not so strong a fish as the sal- 
mon, nor does it reach so large a size. Although 
naturally anadromous, like the true salmon, land- 
locked forms of the salmon-trout are not un- 
common. These have been usually regarded as 
different species, while aberrant or intermediate 
individuals are usually regarded as hybrids. 
The present writer has examined many thou- 
sands of American Salmonide, both of Oncorhyn- 
chus and Salmo. While many variations have 
come to his attention, and he has been compelled 
more than once to modify his views as to specific 
distinctions, he has never yet seen an individual 
which he had the slightest reason to regard as a 
“hybrid.” It is evident that in America but few 
species of salmonoids exist, and that these are 
subject to many variations. It is certainly illogical 
to conclude that every specimen which does not 
