394 



MORRIS M. WELLS 



The other species of Acmea showed the same type of behavior 

 as that indicated for spectrum; they showed also, the same 

 wide variation in the behavior of different individuals. Figure 

 3 is a graph plotted from the data furnished by an individual 

 of Acmea scabra. This individual was located on a vertical 

 face of rock and was subjected to the direct dash of the waves. 



It will be noted that the animal whose behavior is indicated 

 in Fig. 3 was found in the same spot from the 5th to the 12th 

 day and then, after moving about for four days, settled down 

 again and on the 30th and last day of the observational period 

 was still to be found in this second resting place. 



16-30 



$-12, 



Fig. 3. — Graph of the movements of an individual of Acmea scabra. 

 once a day. 



Readings 



The foregoing experiments indicate that the limpets of the 

 genus Acmea possess a rather definite homing instinct which 

 is displayed by certain individuals more than by others; the 

 other data serve to confirm this view. 



The species Lottia gigantea was found to be a very consistent 

 homer with the individual variation reduced to a minimum. 

 Seven individuals of this large species were marked and observed 

 daily for 25 days. These animals were located on the exposed 

 side of an immense boulder, and were subjected to the direct 

 influence of the incoming waves very soon after the turning of 

 the tide. The exposed position made observation of actual 

 movements rather difficult, for like the other species, Lottia 

 gigantea moves only when moistened by the waves. 



The low-tide observations upon the seven individuals of 



