ON THE LOCOMOTION OF A SEA ANEMONE 

 (METRIDIUM MARGINATUM). 1 



J. F. McCLENDON. 



Last winter while studying some animals in the marine aquaria 

 of the University of Pennsylvania I noticed that the anemones, 

 after being placed at the bottom of an aquarium, would creep up 

 the side of the glass to a more favorable position. Their method 

 of progression is similar to the ordinary creeping of a snail, 2 con- 



FlG. I. AL'tridiiun inai^ino/iini seen through the glass, up which it is creeping. 

 The lower side of the photograph has been outlined. 



sisting of a succession of waves that travel from behind forward, 

 but in the anemone the waves are larger and not so rapid or 

 regular. The accompanying photographs were taken of an 

 anemone creeping up the side of an aquarium, with its distal 

 end inclined forward, probably to test the water into which it 

 was advancing. The undulations of the foot progress in the 

 direction of locomotion. If the functionally posterior end of the 



1 Contribution from the Zoological Laboratory of the University of Pennsylvania. 



2 For a more complicated form of locomotion in some snails see A. J. Carlson : 

 "The Physiology of Locomotion in Gasteropods," BIOL. BULL., Vol. 2, January 



1905, pp. 85-93. 



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