236 



WILLIAM LAWRENCE TOWER. 



TABLE III. 



SHOWING IN CULTURE T 100, THE COMPLETE FAILURE OF SURVIVAL IN THE POPU- 

 LATIONS OF THIS CULTURE AFTER Six GENERATIONS IN THE 

 DESERTS OF TUCSON. 



TABLE IV. 



SHOWING THE RESULTS OF THE TESTS IN CULTURE T 100 A, IN WHICH ELIMINATION 

 DURING HIBERNATION is SHOWN TO INCREASE PROGRESSIVELY, ENDING IN A 

 CONDITION IN WHICH SURVIVAL OF THE WINTER AT CHICAGO is NO LONGER 

 POSSIBLE FOR THE POPULATIONS IN THIS CULTURE. 



TABLE V. 



SHOWING THE SURVIVAL TESTS MADE IN THE SECOND, FOURTH, SIXTH AND EIGHTH 

 GENERATIONS OF THE CULTURE T ioo B, IN WHICH THE PROGRESSIVE INCREASE 

 IN THE ELIMINATION DURING HIBERNATION FROM THE SECOND TO THE EIGHTH 

 GENERATION, RESULTS IN COMPLETE ELIMINATION IN THE LAST Two TESTS 

 MADE IN THIS SERIES. 



