Kendall. — Blue Pike and Yellow Pike 263 



of the six individual yellow pike has the narrower interorbital, 

 which corresponds to the interorbital of the largest blue pike. 

 Eye. — The length of the eye affords the clearest example of 

 the manner in which the blue pike differs from the yellow pike. 

 In the general averages there is a uniform decrease in size of 

 the eye with the increase in size of both forms, the blue pike 

 having the larger eye of the two. Here the very smallest of 

 the yellow pike has eyes equal to the average as shown in 

 Group 3 of the blue pike, and the very largest blue pike equals 

 Group 3 of the yellow pike. As to eyes, the six individuals of 

 each kind are widely different, comparatively speaking; the 

 blue pike have constantly the larger eye, though in this kind 

 it is the most variable. The larger eye of the blue pike is a 

 youthful characteristic, as all young fishes have proportionally 

 larger eyes than adults. 



BODY PROPORTIONS 



The only dimensions to which I shall refer in this con- 

 nection are the position of the ventral and anal fins and the 

 distance between dorsals. 



Distance from Base of Pectoral Fin to Base of Anal Fin. — 

 The distance from the base of the pectoral fin to the base of 

 the anal fin, as shown by the general averages, is greater in the 

 blue pike than in the yellow pike, but the dimensions are 

 equal in the different groups. The blue pike of Group 1 with 

 an average length of 296 mm. equals the yellow pike of Group 

 4 of 331 mm., and the blue pike of Group 4, averaging Z67 

 mm., equals Group 5 of the yellow pike which averages 416 

 mm. in total length. 



In the six individuals of each form, the same tendency to 

 increase the distance with increase of size of the fish is main- 

 tained, as in the general averages, and the blue pike maintains 

 the greater dimension. In this characteristic, the blue pike is 

 the more variable, and it is the smaller blue pike which equals 

 the larger yellow pike. 



A blue pike 295 mm. long is slightly less in this dimension 



