1895.] Leuciscus Balteatus, A Study in Variation. 11 
od 
teeth of the Cyprinide offer another striking example of these 
variations among the Pacific slope species. In a number of 
cases, the variations of the Pacific slope species extend along 
definite and parallel lines. I have pointed out some of these 
in the paper quoted above. These lines are directed towards 
an increase of rays and towards a modification of rays into 
spines. 
\ The following quotations, from Gilbert and Evermann’s re- 
cent work on the Columbia River Basin,’ illustrate the varia- 
tion among the different specimens of the same species. “The 
range of variation seems to be very great, and characters which 
are of undoubted specific value when applied to Atlantic drain- 
age species, do not possess any such value for classification of 
Pacific coast fishes. Each so-called species seems to be in a 
very unstable state of equilibrium, and not to have yet as- 
sumed or been able to retain, with any degree of permanence, 
any set of specific characters.” “'The crosswise series of scales 
[in Agosia nubila (Girard)]. varies from 47 to 70 in number; 
the barbel [a generic character] is present or absent; the 
pharyngeal teeth vary from 1,4-4,0 to 2,4-4,1 ; and the dorsal 
fin varies much in position and somewhat in size. These 
characters occur in various combinations, and with some of 
these are often correlated peculiarities of physiognomy and 
general appearance, all of which may serve to put a certain 
stamp upon the individuals from a single stream, or even from 
one locality in a stream.” These observations, especially those 
contained in the last sentence, accord exactly with the results 
obtained by me in Leuciscus, and confirm my statement 
which will be further reénforced by the present paper, “ that 
each locality has a variety which, in the aggregate, is different 
from the variety of every other locality.” 
The remarkable variation of the Pacific slope species, and 
more especially the variation in the fin rays, was first noted in 
preparing my account of the specimens collected in the Colum- 
3 Report of the Commisssioner of Fish and Fisheries on havai in the 
Columbia River Basin in Regard to the Salmon Fisheries. Washington, 1894. 
A report upon investigations in the Columbia River Basin, with deseription of 
four new ene of fishes. 
