BEHAVIOR OF THE LOWER INVERTEBRATES 413 



There seems to be a correlation between the specific reactions 

 of the species and their habitats. In all the species the behavior 

 is repeatedly modified owing, in the opinion of the author, to 

 " increased sensitiveness on the part of the animals." 



Putter (32) has given a resume of experimental work on the 

 irritability of protozoans. 



In the course of a detailed study of the structure of the in- 

 fusorian Diplodinium, Sharp (33) records several observations 

 on locomotor activity and the action of the membranellae. 



Torrey and Hays (34) find that Porcellio scaber is negative 

 in its reaction to light and may be driven about in any direc- 

 tion by light coming from behind. The first reaction of the 

 animal when light is suddenly flashed upon it is to turn directly 

 away. Orientation, the authors conclude, is direct although the 

 method may be obscured by various random movements. 



In the course of an account of the influence of various chem- 

 icals on Colpidium colpoda, Weyland (35) describes results of 

 experiments on the chemotaxis of the species in relation to a 

 considerable variety of compounds. 



Zagorowsky (36) finds that Paramecia are positively thermo- 

 tactic up to 32° C. but at 33° C. and above they become nega- 

 tive. The rate of swimming increases with rise of temperature 

 up to 49° C. after which it rapidly falls and ceases at 55° C. 



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