46 SCIENCE SKETCHES. 
specific names, in giving to these animals a scientific 
nomenclature. Since Steller’s time, writers of all 
degrees of incompetence, and writers with scanty 
material or with no material at all, have done their 
worst to confuse our knowledge of these salmon, 
until it became evident that no exact knowledge of 
any of the species remained. In the current sys- 
tem of a few years ago, the breeding males of the 
five species known to Steller constituted a separate 
genus of many species (Oncorhynchus Suckley) ; the 
females were placed in the genus Sa/mo, and the 
young formed still other species of a third genus, 
called Fario, supposed to be a genus of trout. 
The young breeding males (gri/se) of one of the 
species (Oxcorhynchus nerka) made still a fourth 
genus designated as Hypsifario. Not one of the 
writers on these fishes of twenty-five years ago 
knew a single species definitely, at sight, or used 
knowingly in their descriptions a single character 
by which species are really distinguished. Not less 
than thirty-five nominal species of Ovzcorhynchus 
have already been described from the North Pa- 
cific, although, so far as is now known, only the 
five originally noticed by Steller really exist. 
The descriptive literature of the Pacific salmon 
is among the very worst extant in science. This 
is not, however, altogether the fault of the authors, 
but it is in great part due to the extraordinary 
variability in appearance of the different species of 
salmon. These variations are, as will be seen, due 
to several different causes, notably to differences 
in surroundings, in sex, and in age, and in con- 
ditions connected with the process of reproduction. 
