AN ANALYSIS OF THE SPAWNING HABITS AND 



SPAWNING STIMULI OF CUMINGIA 



TELLINOIDES. 1 



BENJAMIN H. GRAVE, 

 WABASH COLLEGE (SEESSEL FELLOW 1926-1927). 



Since the discovery of a slight lunar periodicity in the spawning 

 of Chxtopleura apiculata, the writer has studied the spawning 

 seasons of a considerable number of animals in the hope of 

 finding other more clearly marked cases. The conclusion of this 

 study is that the phenomenon is of rare occurrence at Woods 

 Hole. Cumingia tellinoides is the one species studied critically 

 to date that shows a lunar periodicity. Three other species 

 whose study has been completed show absolutely no periodicity. 

 Others being studied require further investigation before they 

 can be passed upon with any degree of certainty. If semi- 

 scientific reports are trustworthy, this type of periodicity is much 

 more common in the tropics, since several fairly well authenti- 

 cated cases are reported from the Tortugas and elsewhere. 



A part of the data presented in this paper was read before the 

 American Society of Zoologists at their annual meeting in 

 December, 1922. Since that time the study has been continued 

 and the results are finally presented for publication in their 

 completed form. 



SECTION I. 



THE SPAWNING SEASON. 

 The Duration and Characteristics of the Spawning Season. 



Cumingia begins to spawn about the middle of June and 

 continues with variations of activity until the middle of Sep- 

 tember and sometimes until the first of October. During 1926 

 the first eggs were obtained on June 21 and the last ones on 

 September 21. The heaviest spawning occurs during the last 



1 From the Osborn Zoological Laboratory, Yale University, New Haven, Conn., 

 and the Marine Biological Laboratory, Woods Hole, Mass. 



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