285 



lakes, the preferences shown for a given number of spines are ([uite different. 

 In the Tippecanoe Lake specimens the preference is decidedly for 14. In tlie 

 Turkey Lake specimens the preference is for 15, although not so decided. From 

 Table IV and the curves, it will be seen that the number of individuals in Tur- 

 key Lake having 14 spines and 15 spines are about the same, 41 per cent, having 

 14 and 44 per cent., 15, while in Tippecanoe Lake this is not the case, 60 per 

 cent, having 14, and only 25 per cent, having 15. 



TABLE IV 



si 3 rt 



3 a, *> 



Per cent, of specimens having 12 dorsal spines 

 Per cent, of specimens having 13 dorsal spines 

 Per cent, of specimens having 14 dorsal spines 

 Per cent, of specimens having 15 dorsal spines 

 Per cent, of specimens having 16 dorsal sjiines 

 Per cent, of specimens having 17 dorsal spines 



0.32 



5.09 



41.26 



44.22 



6.90 

 0.65 



0.38 



11.24 



60.85 



25.96 



1.16 



0.38 



Dorsal Rays.— The average number of dorsal rays for Turkey Lake is 14.87, 

 for Tippecanoe Lake, 16.40, the latter having on an average almost two more. 

 The curves are given in Fig. 4. From this and Table V it will be seen that Tur- 

 key Lake specimens show a decided preference for 15 rays, while the Tippecanoe 

 Lake specimens show just as decided a preference for 16 rays, 52 per cent, of the 



