SPAWNING HABITS OF CUMINGIA TELLINOIDES. 



425 



12 Isolated Individuals 

 Spawned as Follows. 



12 Individuals in Common 

 Dish Spawned as Follows. 

 One male at 1:32 P.M. 



One male at 1:55 P.M. 

 One male at 1:57 P.M. 

 One male at 1:58 P.M. 

 One male at 1:59 P.M. 

 One female at 2:00 P.M. 

 One male at 2:05 P.M. 

 One male at 2:08 P.M. 

 One male at 2:09 P.M. 



Time Elapsed 



before Spawning. 



2 minutes 



1:48 P.M. one male 18 



25 



27 



i -.58 P.M. one male 28 



1:59 P.M. one male ... 29 



30 



35 



38 



39 



2:10 P.M. one female 40 



2:13 P.M. one female 43 



2:15 P.M. one male 45 



2:16 P.M. one male .... 46 



2:17 P.M. one female 47 



2:20 P.M. one female 50 



2:22 P.M. one female 52 



Comment: Two of the isolated individuals and three in the 

 common dish did not spawn within an hour. As a matter of 

 chance most of the females got into the isolated dishes. 



SECTION III. 



NATURAL SPAWNING STIMULI. 

 /. Lunar Periodicity. 



If Cumingia spawns most frequently at the period of the full 

 moon, it is evident that there is some cosmic stimulus which 

 varies with the moon's phases to which spawning is due. The 

 two chief variable quantities are light, and tides, or pressure. 

 There is at present no scientific explanation of lunar periodicity 

 although numerous cases are known,. 



It has been the writer's chief interest during the past five 

 years to learn whether the phenomenon is rare or of common 

 occurrence among animals at Woods Hole. The data bearing on 

 this subject are given in a short forthcoming paper, but the 

 findings in reference to Cumingia are given here in greater 

 detail. 



A careful study and comparison of data collected during the 

 past five years shows that there is a lunar periodicity in spawning, 

 although it is not as well marked as in Nereis limbata or the 

 Suez sea urchin studied by Fox. 



