No. 645] VERTEBRA OF FISHES 



367 



9.53 (+0.06) for 19198 females, and 9.69 (+0.03) for both 

 sexes of the 19199 class ; in material collected in 1902 in 

 the same lagoon the average is still higher, 9.83 (+ 0.02). 

 The data on which these figures are based is given in Fre- 

 quency Table I. In all three characters, namely the num- 

 ber of vertebrae, of scales along the lateral line, and of 

 branched anal rays, the year-class developed in the cooler 

 season displays a significantly higher average. 



A highly similar yet exactly reverse condition is dis- 

 played in the analysis of the counts on the Lepomis in- 

 cisor material. In this case the total number of vertebrae, 

 and the number of caudal, but not precaudal, vertebrae ; 

 the number of dorsal spines, dorsal soft-rays, anal soft- 

 rays, and hence the total number of vertical fin-rays, all 



average higher in the class bom in 1918 than in that of 

 1919. But we noted above that the temperature relations 

 during the developmental periods of the two years were 

 likewise reversed. In both Notropis atherinoides and 



