336 Papers from the Marine Biological Laboratory at Tortugas. 



Eighth trial: (Immediately afterwards). Very definitely done. Time: 

 3 minutes. 



Ninth trial: (Immediately afterwards). Shoved cardboard aside with 

 beak. Time: 0.16 minute. 



Tenth trial: (Immediately afterwards). Opened with beak. Time: 0.16 

 minute. 



The above experiment was repeated on the mate (unmarked) of this bird. 

 Its time was very much better than that of the marked bird. 



First trial: Flew against the cardboard and knocked it over immediately. 

 Time: 5 minutes. 



Second trial: Flew against it vigorously. The wind assisted it. Time : 7 

 minutes. 



Third trial: This bird worked ten times harder than mate. Flew against 

 the cardboard very definitely. Time : 3 minutes. 



Fourth trial: Not a useless movement. Time: o.io minute. 



Fifth trial: Interrupted work twice to drink. Time : 3.50 minutes. 



The above trials were all given on the first day and in immediate succes- 

 sion. This change in method was necessitated by the increasing shortness 

 of my stay. 



Sixth trial: (One day later). Flew against cardboard, the wind aiding 

 it. Time: 1.50 minutes. On account of the wind, no further tests were 

 made that day. The heavy winds continued for six days and the experi- 

 ments had to be discontinued. 



Seventh trial: (Six days later). Opened by flying against it. Time: 

 6.50 minutes. 



Eighth trial: Opened by flying against it. Time : 9.68 minutes. 



Ninth trial: (One day later). Time: 7 minutes. 



Tenth trial: Time : i minute. 



Eleventh trial: Time : 0.75 minute. 



No further tests were made on this bird. Useless movements were 

 rapidly eliminated during the first five trials given on the first day. Appar- 

 ently these five tests and the one given on the following day were not suffi- 

 cient to fix the association definitely enough for it to be carried over the 

 six days in which no trials were given. The test is suggestive of a very low 

 order of retentiveness. 



Other problems were submitted to the noddies in a similar way, but the 

 results were not sufiiciently definite to report. In conclusion, however, we 

 may say that the above method ought to Ije one of great importance in ob- 

 serving the reactions of the noddies under conditions of control. By it I am 

 sure that in the end we may gain a knowledge of the variety and the com- 

 plexity of the problems which the noddy can learn. The method would 

 work equally well with respect to the length of time which such associations 

 can be retained. 



