CONTRIBUTIONS FROM THE ZOOLOGICAX, LABORATORY OF THE MUSEUM OF COMPARATIVE ZOOLOGY AT 

 HARVARD COLLEGE. NO. 291, 



THE RHYTHMIC CONTRACTIONS IN THE MANTLE OF 

 LAMELLIBRANCHS 



ELIZABETH S. P. REDFIELD 



FOUR FIGURES 



INTRODUCTION 



The respiratory currents through the mantle chamber of the 

 lamelUbranchs have been attributed exclusively to the action of 

 the ciliated epithelium, covering the mantle, gills, and foot. 

 Kellogg ('15) has recently made a thorough study of these cur- 

 rents and it appears from his work that they have a dual func- 

 tion; to supply water to the gills and to remove foreign matter 

 from the mantle chamber. 



Babak ('13, p. 197) has called attention to rhythmic move- 

 ments of the shells of lamellibranchs, to which he attributes a 

 cleansing function. 



Die Schalenbewegungen, welche zuweilen gleichsam rhythmisch iind 

 in auffalliger Frequenz erscheinen, haben (wenigstens bei Anodonta und 

 Unio) kaum irgendwelche grossere respiratorische Bedeutung, da sie 

 gerade im sauerstoffarmen Wasser nicht vermehrt werden, obwohl durch 

 den auf diese Weise erfolgenden Wasserwechsel unzweifelhaft eine 

 machtige Forderung des Gaswechsels zustande kommen wiirde. Es 

 lasst sich dartun, dass die Schalenbewegungen haiiptsachlich als Reinig- 

 ungs-reflexe aufzufassen sind. 



This paper is a description of certain rhythmic movements 

 found in the mantle of several species of lamellibranchs, and of 

 experiments to determine the function of these movements. 

 The recent summary of work on the respiration of lamelUbranchs 

 by Babak ('12) makes no mention of this phenomenon, which 

 apparently thus far has passed undetected. 



I wish to thank Dr. George Howard Parker, under whom this 

 work has been done, for his assistance, and the United States 



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