LOCOMOTION OF A SEA ANEMONE. 67 



foot be watched closely it will be seen to let go at several points 

 (below in Fig. i ) and slip forward. This contraction is carried 

 forward and on reaching the center of the foot, the contracted 

 portion rises up from the glass, forming a wave that deepens as 



FlG. 2. Metridiiim marginatum about half a minute later than Fig. I. 



it approaches the "anterior" end (Fig. 2, above). On reaching 

 the " anterior " edge the wave is retarded by the firmer attachment 

 of the edge, which releases locally, breaking the wave into seg- 

 ments (Fig. i, above). A wave requires about a minute to trav- 

 erse the foot of the anemone, and before it has disappeared, 

 another commences. 



I threw a number of anemones into an aquarium to observe 

 their actions. They threw out acontia, which caught hold of 

 any solid near them and contracted until some portion of the foot 

 touched the object and caught hold. One anemone sinking to 

 the bottom and resting on its tentacles contrived to rierht itself 



o 



by suddenly contracting and expelling water from its mouth. I 

 observed this once or twice subsequently, but rather think it a 

 coincidence than a common reflex. 



BIOLOGICAL HALL, UNIV. OF PENN., 

 December 5, 1905. 



