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THE AMEBIC AN NATURALIST [Vol. XLII 



to hatch, through 24 consecutive hours, beside several ob- 

 servations of lesser duration. 



In these observations, I was aided by Dr. C. F. Hodge 

 and Mr. Newton Miller, who kindly gave me occasional 

 resting periods. 



The first set of observations which I shall record were 

 made on May 16-17, 1908. 



Observation was begun at 6 P. M. on two crawfish, a 

 male and a female with eggs about ready to hatch, and 

 lasted until 6 A. M. the following day. In the aquarium 

 with the crawfish, were the water hyacinth and Fontinalis 

 mentioned above, some young sprouts, five young toad 

 tadpoles, and some pieces of fresh meat. 



The male was moderately active between 8.10 and 8.45 

 P. M., most active between 12. and 1.30 A. M., and had 

 a lesser period of activity between 2.05 and 2.30 A. M. 

 The longest period of quietude was from 1.30 to 2.10 

 A. M. lie ascended and descended the bank nine times 

 during the 12 hours. The male did not feed. 



The female ascended and descended the bank 84 times 

 during the 12 hours. She ascended and descended 17 

 times between 1 and 2 A. M. She would climb the bank 

 and aerate her eggs in the open for several moments, then 

 retire to the deep water and almost immediately return to 

 the bank. The greatest activity was from 11 P. M. to 6 A. 

 M. She fed at 6.50 and again at 7.07 P. M. both times on 

 the fresh meat. Her longest rest period was from 10.30 to 

 to 11 P. M. 



The next series of observations was performed on three 

 crawfish, the two observed on May 16-17, and in addition, 

 a female without eggs. This time observation was kept 

 up for 24 consecutive hours, from 1 P. M. May 19, to 1 P. 

 M. May 20. 



The same kind of food was used as before, care being 

 taken to avoid fouling the water with it until about one- 

 half hour before the records were taken. 



The male fed a great deal this time on the fresh meat, 

 feeding from 1.35-2.15 P. M., 2.30-245 P. M., 3.18-3.40 P. 



