SPAWNING HABITS OF CUMINGIA TELLINOIDES. 423 



It is the writer's belief that the spermatozoa have no effect. 

 The mechanical shock of removing the animals from their 

 normal situations furnishes all the stimulus that is required to 

 induce spawning. There is no perceptible stimulus from the 

 opposite sex either chemical or physical. This is shown by a 

 series of experiments designed to test the theory. The three 

 described herewith are representative. The method was to 

 collect Cumingia in large numbers. Half of them were isolated in 

 small stender dishes and covered with sea water in the usual way. 

 The other half were treated in the same way except that they 

 were all put in a large crystallization dish so that they might 

 receive chemical stimuli from each other if such exist. The time 

 of spawning is shown in the two columns of the tables and they 

 may be readily compared. 



Experiment No. I. 



August 21. Collected 20 Cumingia. Ten were isolated in 

 stender dishes and ten were placed in a common dish. Experi- 

 ment set at 12:30 P.M. 



10 Isolated Individuals Time Elapsed 10 in Common Dish 



Spawned as Follows. before Spawning. Spawned as Follows. 



1:15 P.M. one female 45 minutes 



1:16 P.M. one male 46 



i :20 P.M. one male 50 



i :23 P.M. one male 53 



55 One male shed 1:25 P.M. 



57 One male " 1:27 P.M- 



i :29 P.M. one female 59 



60 One male " 1:30 P.M. 



61 One female " 1:31 P.M. 



67 One male " 1:37 P.M. 



68 One male " 1:38 P.M. 



70 One male " 1:40 P.M. 



71 One female " 1:41 P.M. 

 i :55 P.M. one female 85 



2:05 P.M. one female 95 



Comment: Three of the isolated individuals and two in the 

 common dish failed to spawn. Comparison shows that those in 

 the common dish did not spawn more promptly than the isolated 

 individuals. It is noteworthy that those in the common dish 



