424 



BENJAMIN H. GRAVE. 



spawned close together in point of time. 

 Experiment No. 3, but not in No. 2. 



This was also true in 



Experiment No. 2. 



August 27. Collected 34 Cumingia. Isolated seventeen in 

 stender dishes and placed seventeen in a common dish. Experi- 

 ment set at 5:55 P.M. 



17 Isolated Individuals Time Elapsed 17 in Common Dish 



Spawned as Follows. before Spawning. Spawned as Follows. 



30 minutes One female at 6:25 P.M. 



One male at 6:27 P.M 32 



One male at 6:28 P.M 33 



One male at 6:29 P.M 34 



35 Two males at 6:30 P.M. 



36 One male at 6:31 P.M. 

 One female at 6:32 P.M 37 



38 One male at 6:33 P.M. 



39 One male at 6:34 P.M. 

 41 One female at 6:36 P.M. 



One male at 6:37 P.M 42 One male at 6:37 P.M. 



One female at 6:37 P.M 42 



One male at 6:39 P.M 44 



47 One male at 6:42 P.M. 



48 One male at 6:43 P.M. 

 One male at 6:44 P.M 49 



One female at 6:45 P.M 50 



Two males at 6:46 P.M 51 One female at 6:46 P.M. 



52 One female at 6:47 P.M. 



55 .' One male at 6:50 P.M. 



One female at 6:51 P.M 56 



One female at 6:54 P.M 59 



Comment: Five isolated individuals did not spawn within the 

 hour and five of those in the common dish did not spawn. There 

 is no evidence that they receive a chemical stimulus from each 

 other calculated to induce spawning. They spawn as readily 

 when isolated as when in the same water. 



Experiment No. j. 



August 28. Collected 24 Cumingia. Isolated twelve in stender 

 dishes and placed twelve in a common dish. Experiment set 

 at 1:30 P.M. 



