642 The American Naturalist. [August, 
Evolution of the Color Pattern. 
As just stated, the point of greatest variability is the color 
pattern. The colors in life are not taken into consideration, 
but only the black markings which were preserved in alco- 
holic specimens. On comparing living specimens with alco- 
holic material, but little difference was noticed. In the matter 
of color patterns, the specimens from any one locality agree to 
a remarkable extent. This statement refers only to specimens 
of the same size—differences, of course, existing between young 
and adult stages. 
The simplest pattern was found in specimens from Chocola 
Cr., Ala. These were immature specimens, and do not represent 
the adult condition. ; 
In these specimens (30 and 33 mm. long., fig. 1), we have 
a series of nine cross-bars extending from the back to below 
the middle of the sides. The bars at the ends of the dorsal 
fins are much emphasized, and all the bars are heaviest at 
their upper and lower ends. There is a distinct round spot 
at the root of the caudal. The color of the head need not be 
taken into consideration in this specimen. The caudal spot 
remains in all the specimens examined. The most compli- 
cated pattern, that of fig. 7, is shown to-be derived by easy 
stages and step by step from the condition figured in fig. 1. 
The simplest pattern in adult fishes is found in specimens 
inhabiting the waters of the Wabash River and its tributaries 
in Indiana (Nos. 9, 40 and 44). The pattern here consists of 
a series of long and short bars alternating. In the anterior 
region, the short bars are usually as long as the long bars. A 
better way to designate these is to term the long bars “ whole 
bars," and the short bars “ half bars" The whole bars towards 
the posterior end of the body spread slightly and become more 
intensely colored toward their ventral extremity. The black 
caudal spot is also present here. This spot does not vary in 
any of the patterns figured. The head is colored black above, 
and has a large spot on the opercle, taking the general form of 
the opercle itself. The color on the top of the head is most 
intense towards the posterior, as shown in fig. 9, and becomes 
less less distinct as it extends forward to the tip of the snout. 
