American Fisheries Society. 51 
margin of the scale that corresponds to the bow-string is di- 
rected towards the head in the natural position of the scale and 
we may eall it the cranial border of the scale. The rest of the 
margin, corresponding to the bow, forms a continuous and more 
or less smooth curve, but may be divided into three parts. One 
of these looks towards the tail in the natural position of the scale 
and is the caudal border. One is directed towards the back of 
the fish, the dorsal border, and the other toward the belly, the 
ventral border. 
Somewhere near the center of the scale is a small, smooth 
area, which represents the center of the original scale of the 
young fish to which additions have been made from time to 
time by the growth of the scale. This smooth area may be called 
the growth center of the scale. Between the growth center and 
the border are numerous fine striations which form concentric 
lines parallel to the border and, like the rings in a tree, mark 
successive stages in the growth of the scale. Running from the 
growth center to the margin are four radiating ridges which 
divide the surface of the scale into four triangular areas. Hach 
of these areas is bounded by one of the four borders of the scale 
and the areas may be called therefore the cranial, caudal, dorsal, 
and ventral areas. In the natural condition three of these areas, 
the cranial, dorsal and ventral, are covered by the overlapping 
of adjacent scales and only one, the caudal, is visible when the 
scales are in position in the fish. 
The characters mentioned as belonging to the typical scales 
are common to both of the species under discussion but the scales 
of each species differ from those of the other in certain char- 
acters which enable one to distinguish them. 
Among the typical scales there are a few in which the central 
part of the scale is occupied by an irregularly granular aree 
which has a diameter half that of the scale and suggests a great- 
ly enlarged growth center. Scales of this sort were probably 
formed after the fish had grown to some size and in place of 
scales that had been lost. They should not be taken into account 
in attempting to separate species by the scales. 
In all the menominees the growth center is in the center of 
the scale, midway between the cranial and dorsal borders. In all 
of them the caudal border is strongly crenated (or scalloped) 
