SOME POINTS REGARDING THE BEHAVIOR 

 OF METRIDIUM. 



LULU F. ALLABACH. 



It has recently been shown that the reactions of many sea 

 anemones are modifiable, in dependence on a variety of internal 

 conditions (Jennings, 1905). The purpose of the work here pre- 

 sented was to determine how far similar relations hold for Mctri- 

 dinni niarginatinn. Since jMctridimn is the commonest of our 

 sea anemones, and the one most used in investigation and in- 

 struction, it is important that its behavior should be well known. 

 The work was suggested by Dr. H. S. Jennings, and carried out 

 under his direction at the Marine Biological Laboratory at 

 Woods Hole. 



I. CHANGES IN THE REACTIONS TO CERTAIN SORTS OF 



FOOD BODIES. 



The point to which experimentation was first directed was the 

 interpretation of the results of certain experiments of Nagel 

 (1892) and Parker (1896). In Parker's experiments alternate 

 pieces of meat and filter paper (soaked in meat juice) were given 

 to the tentacles of one side of the disk of Mctridiuin. It was 

 found that while the meat was swallowed each time with equal 

 readiness, the time taken in swallowing the paper increased, and 

 after three or four trials the animal no longer ingested the paper, 

 though the latter contained each time the same amount of meat 



o 



juice as at first. After reaching this result with the right side 

 of the disk, the same series of experiments was performed on the 

 opposite side of the disk of the same specimen. It was found 

 that the left side* had not become modified by the experience of 

 the right side. It at first took the paper, then by the same 

 gradual change seen previously on the right side, it came to 

 refuse the paper. A series of records of the times required for 

 swallowing the meat and paper in such an experiment by Parker 

 are given in the following table : 



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