1880. ] Zoblogy. 367 
Pacific coast salmon is seventeen, as in the European salmon and 
all trout. 
Now there are five species of Oncorhynchus on this coast, and 
of these three are more or less hump-backed. All five are found 
in the Columbia, but they do not all inhabit Californian rivers. 
The common species, the guinnat, is not hump-backed. Onco- 
rhynchus nerka, a somewhat hump-backed species with scales of 
about the same size as those of the guinnat, is on record from 
the rivers of California, but I have not yet detected its presence 
in our markets. This species grows as large as the common sal- 
mon, and is more cylindrical in form. 
The hump-back now in the market is not this species. It has 
very small scales in more than two hundred transverse rows, is 
exceedingly compressed and thin in the body, has an excessively 
developed hump, and, so far as I have observed, does not reac 
the dimensions of the guinnat. These characters, taken together, 
prove that it is the species now known as Oncorhynchus gorbuscha. 
ay here remark that the species of salmon and trout are 
probably more difficult to distinguish than those of any other 
tribe of fishes, partly because of the changes they undergo with 
season, as was previously observed, the lower jaw o 
: y, 1861, and the proteus of Pallas, 1811. This 
IS par excellence the hump-back salmon, does not attain a large 
size, and is on record as ranging from Washington to Kamt- 
schatka. Its occurrence in our markets proves that in the 
autumn it visits the neighborhood of San Francisco. The dealers 
tell me it is taken in the Sacramento. O. keta, which is on recor 
ht 
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5 
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Notwithstanding the diminution in the apparent number of the 
Pacific coast Salmonidæ (taking the word in the sense it was used 
