JOURNAL OF ANIMAL BEHAVIOR 



Vol. 6 NOVEMBER-DECEMBER No. 6 



LITERATURE FOR 1915 ON THE BEHAVIOR OF 

 THE LOWER INVERTEBRATES" 



W. H. TALIAFERRO 



From the Zoological Laboratory of the Johns Hopkins University 



Allen (1) finds that Planaria dorotocephala reacts both posi- 

 tively and negatively to a stream of water. ' The sign of the 

 reaction may differ depending upon the velocity of the current." 

 In such cases the author finds that they are positive to the 

 stronger current and negative to the weaker one, and that often 

 when a given specimen is reacting negatively to a weak current 

 it can be made positive by increasing the velocity of the cur- 

 rent. A positive reaction can be changed to a negative one by 

 a change in the composition of the aquarium water and can be 

 again reversed by the resumption of the former conditions. 

 Similar reversals can be effected by sudden temperature changes. 



The sudden appearance and disappearance of vast numbers 

 of Folliculina on the aquatic plants along the shores of the 

 Chesapeake Bay and its branches that were noted by Andrews (2) 

 in 1912 and 1913 occurred again in 1914. The time of appear- 

 ance and disappearance differs in successive years. The author 

 is of the opinion that the large numbers of this protozoan are 

 due more to immigration from without than to the division of 

 the organisms that have already settled on the plants. ' It is 

 suggested that conditions of food possibilities are determining 

 factors in these inroads into the brackish fauna." 



Bittner, Johnson, and Torrey (3) hold that the one thing 

 fundamental to all tropism hypotheses is that the movements 

 in orientation should be predictable as to direction, and they 



