286 



specimens having these numbers in both lakes. The range of variation is two 

 greater in Turkey Lake, from 1'2 to 18 as compared from 14 to 18 in Tippecanoe 

 Lake. This again may be due to the greater number of specimens. 



TAI'.LE V. 



3§ 



o a 



a 

 a 



0) ^ 



o 



^ 



Per cent, of specimens having 12 dorsal rays 

 Per cent, of specimens having 13 dorsal rays 

 Per cent, of specimens having 14 dorsal rays 

 Per cent, of specimens having 15 dorsal rays 

 Per cent, of specimens having Iti dorsal rays 

 Per cent, of specimens having 17 dorsal rays 

 Per cent, of specimens having 18 dorsal rays 



Table VI presents all the combinations of dorsal spines and dorsal rays from 

 both lakes. The spines are represented by Roman numbers and the rays by 

 Aral)ic numbers. The commonest combination in Turkey Lake is XIV-15 and 

 XV-15; XIV, XV, occurring most frequently in the spinous dorsal, and 15 most 

 frequently in the soft dorsal. The per cent, of specimens having these combina- 

 tions is 22.46 and 24.49 respectively. In Tippecanoe Lake, XIV-16 is the com- 

 monest combination, XIV being the prevailing number in the spinous dorsal and 

 16 in the soft dorsal. 32.11 per cent, of the specimens have this combination. 



