514 



RHYTHMS IN PLANTS AND ANIMALS 



^* — jy* — »y! 



II 



Fig. 10. Periplaneta americana. Rhythms of activity. A period of in- 

 creased temperature (crosshatched, 4 hr from 23° to 32°C) does not shift 

 the phases of the rhythm. Increased temperature from 0-4 (A), 6-10 (B), 

 12-16 (C), or 18-22 (D) hr. = midnight. (Unpublished data.) 



tendrigh (1956) on Euglena, Brown and Webb (1948) on the fiddler 

 crab, of Ball and Dyke (1954) on Avena coleoptiles, of Leinweber 

 (1956) on Phaseolus, and of Hoffmann (1957a) on lizards. 

 Dr. Pittendrigh will doubtless report on his own experiments. Here 



