No. 503] CAMBABUS BARTONIUS HART ONI 715 



M., 3.48-5.00 P. M., 4.10-4.30 P. M. 



He was most active from 11.35. P. M. to 3.15. A. M. 

 It is interesting to note that each period of feeding, if 

 lengthy, was followed by a correspondingly long period of 

 rest. The longest rest period was from 4.45 to 8.05 A. 

 M. The male did not ascend the bank at all during the 

 24 hours. 



The female with eggs began ascending the bank and 

 aerating her eggs at 4 A. M. and stopped at about 4.25 

 A. M., then began again at 6.15 A. M. gradually length- 

 ening the stay on the bank until 9 A. M. then shortening 

 the frequency of the visits, and lengthening the stay in 

 the water; this period of less frequent visits lasted until 

 11 A. M., then from 11 A. M. to 12 M., there was great 

 regularity of aeration, and from 12 M. to 1 P. M., less 

 frequent aeration. Ascent of the bank was made thirty- 

 four times during the 24 hours. 



Feeding was done at 1 :45 P. M., and again at 2.15 P. M., 

 but in neither case did it last longer than ten minutes. 



Number seven, a female without eggs, was very inactive, 

 staying under a stone the greater part of the time. She 

 came out on the bank but three times. Her period of 

 greatest activity was between 3.30 and 4.15 P. M. 



From these observations of the crawfish in nature and 

 in the laboratory, we may conclude as follows: 



1. Crawfish are most active at night. 



2. There is marked activity at nightfall and at daybreak. 



3. Feeding is generally done at night, but may occur 

 during the day. 



4. I?i the spring, the crawfish eats much more often 



5. Cambarus bartonius bartoni prefers fresh animal 

 food to anything else. 



6. Feeding is followed by rest, prolonged periods of 

 feeding being followed by equally prolonged periods of 

 rest, the animal not becoming active for several hours. 



7. There is apparently no spontaneous play or exercise, 

 movements being purely utilitarian. 



