Spaulding, Association in Hermit Crabs. 57 



crabs became most agitated, some hurrying and scurrying about, 

 others making almost directly for one of the openings, A prefer- 

 ence for the right-hand one seemed to exist and this may be con- 

 nected with the right-handed asymmetry. No attempt however 

 to investigate this matter systematically was made, and there 

 were no "landmarks" in the aquarium, such as stones, etc. .where- 

 by a path could be learned. The preceding tabulated results 

 show, (i) the total number each day, (2) the number going 

 into the dark within (3) a certain time, when fed under the con- 

 dition named, (4) the per cent, entering, and (5) for compara- 

 tive purposes, the per cent, entering in one minute. 



' At the end of the 5^ the fish was put behind the screen in order that 

 the association might not be broken up by the crabs entering and finding noth- 

 ing there. When this was done all but one of the eight outside, four of which 

 had gone in and come out again, entered within z' . This was done each suc- 

 cessive day. 



^ Then fed, and in \' all but one had entered. This shows again the con- 

 stant improvement, the learning taking place in a surprisingly short period. 



' In one minute after feeding all of the seven outside had entered. 



* After feeding all entered in 1^3'. 



^ After feeding all but one entered in 2^. 



Accordingly, after the 8th. day, evidence having been thus 

 secured that an association between the two "constructs," food 

 and sense-darkness, had been established, its efficiency was 



