12 The American Naturalist. [January, 
bia and Frazer Basins.‘ This variation was most pronounced 
in the species of the late genus Richardsonius. Of the species 
of this genus, I had about 250 specimens, collected in the Fra- 
zer and Columbia systems, from tidewater to an elevation of 
2,786 feet. The later explorations of Gilbert and Evermann 
have increased this number to 825, and these warrant a re- 
examination of the points stated by me. For all the data con- 
cerning the fin rays of the specimens collected by Gilbert and 
Evermann, I am indebted to them. Their examination of 
these specimens was made to test certain conclusions reached 
by me, and their data, therefore, join mine. In counting the 
anal rays, I counted the rudiments at the beginning of the fin. 
These were not counted by Gilbert and Evermann, and to 
bring their data in perfect accord with mine, it is necessary to 
add 2 to the number of anal rays. While the number of 
rudimentary rays is not always 2, it is so often that the excep- 
tions would probably not alter the general results. 
At the time I began my studies of these forms, they were 
regarded as two species, forming a peculiar genus, Richardson- 
ius. They were known to inhabit the Columbia River and the 
streams about Puget Sound. The compressed belly behind the 
ventral fins was regarded as the character separating them 
generically from the related forms. It soon became evident 
that, while some specimens possessed this, if constant, unques- 
tionable generic character, others did not show it at all, and 
the genus was relegated to the limbo of synonymy. The 
species balteatus and lateralis were distinguished as follows: 
a. Base of anal, 44 in the length ; A. 17 or 18; teeth, 2,5-4,2. 
Lower jaw slightly projecting beyond the upper. Coloration 
plain ; the sides bright silvery; crimson in males in spring. 
Scales 13-62-6. balteatus. 
aa. Base of anal 54 in the length; A. 14; teeth 2,5-5,2. 
Jaws equal; blackish above; a dark lateral band; the inter- 
spaces and belly pale; crimson in male in summer. Scales 
13-55-6. lateralis. 
1 This variation in the same species does not seem to be confined to the Fishes. 
Prof. Ritter, Proc. Cal. Acad. Sci., 2d Ser., Vol. IV, p. 37, finds the same in 
Perophora annectens, a new tunicate described by him. 
