132 'Journal of Comparative Neurology and Psychology. 



significant, and the observations here used were made within 

 fifty-one days (July 11 to August 31) and fall within the general 



.1700 



.16 00 



.1J500 



.MOO 



.1300 



-ISOO 



.UOO 



.1000 



.0900 



.oaoo 



■Xx^eidht of Central Nervous Sysletn. 



.0700 



10 



R.pipiens 



R.esculeitta 



// 

 / / 

 / / 



/ ,' * — ^R.temporaria 



/, 



// 



// 





Body \4'eidhl— dms. 



15 



20 



25 



30 



35 



40 



45 



CHART 2. 

 Showing the weight of the entire central nervous system. 



seasonal limits for constancy, as given above. This summer 

 period is moreover the one during which the central nervous 

 system shows its greatest weight. At the same time it is worthy 



