American Fisheries Society. 4') 
fish, one from Lake Huron, twenty from Lake Erie and one of 
unknown origin; all of legal weight, i.e. two pounds or over. 
It was desired to find some means of separating the white- 
fish and menominees without using the characters founded on the 
head or viscera. The characters given by Jordan and Evermann 
(Fishes of North and Middle America, p. 465) for separating 
these fishes are based wholly or in part on the head, with the 
exception of (1) the color, (2) the number of rays in the dorsal 
and anal fins, and (3) the number of scales in the lateral line 
and of scale rows above and below it. 
The color is so nearly the same in the two species as not te 
afford a rehable means of separating them. ‘The same remark 
apples to the fin rays, in which the individual variations of one 
species overlap those of the other. The number of scales in the 
lateral line and the number of scale rows was found in the 
specimens examined to be insufficient in itself to separate the 
two species, the numbers sometimes coming together or over- 
lapping. 
It seemed essential in order to distinguish the whitefish and 
menominee to make use of some character not hitherto used for 
this purpose. The structure of the scales as they appear under a 
magnifying glass was finally made use of. Five to ten scales 
were removed from each of the fish. In each case the scales were 
taken from the same place, midway between the first dorsal fin 
and the lateral line on the left side. In order to clean them they 
were placed for ten or fifteen minutes in a one per cent. solution 
of caustic potash and were then rinsed and brushed to remove 
any shreds of soft tissue that might adhere to them. Thus pre- 
pared, the scales of each fish were placed between two slides of 
clear glass and these were fastened together by pieces of gummed 
paper. 
If any one of the scales thus prepared be examined with a 
good pocket magnifier giving a magnification of ten to twenty 
diameters the following points may be readily made out. The 
outline of the scale is somewhat that of a bent bow with its 
string. The outline is not straight at any point, but one part 
of it corresponding to the string of the bow is more nearly 
straight than any other part. At its middle this part projects 
into a more or less rounded angle as does the bow string when 
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