AUTHOR S ABSTRACT OF THIS PAPER ISSUED 

 BY THE BIBLIOGRAPHIC SERVICE NOVEMBER 3. 



THE POWER OF SUCTION IN THE SEA-ANEMONE 



CRIBRINA 1 



G. H. PARKER 



ONE FIGURE 



Cribrina xanthogrammica Brandt, the common sea-anemone 

 of the west coast of North America, is remarkable for its powers 

 of suction. If a piece of smooth wood is moved about among the 

 tentacles of an expanded Cribrina, the outer ends of these organ 

 fasten temporarily to the wood by suction and hold to it with no 

 small force. If the finger of the experimenter is used instead of 

 the wood, the tentacles seize it and by contraction attempt to 

 pull it toward the animal's mouth. The feeling of suction where 

 the tentacle is in contact with the finger is considerable. The 

 tentacles attach themselves not only by their tips but also by 

 their sides, especially near their distal ends. Suction at the 

 end of the tentacle seems to be accomplished by a vigorous 

 inversion of the tip, thus forming a pore-like depression. On the 

 sides suction is brought about by the formation of a short verti- 

 cal groove. 



Tentacular suction, as might be expected, is concerned with 

 feeding This is well illustrated by a single example. A small 

 fish about 4 cm. long was liberated in a glass aquarium in which 

 a Cribrina had settled. By accident the fish soon brushed 

 across the tentacles of the sea-anemone, whereupon it was seized 

 and held firmly a few seconds by the sucking ends of the tentacles. 

 Through its struggles it succeeded in escaping, but only to be 

 recaught soon after. Again it escaped, but in a short time was 

 finally caught. It now seemed much weakened and in part 

 paralyzed. Its skin was whitened in many places and shredded. 

 Doubtless it had felt the effects of the actinian's nematocysts. 



'Contributions from the Zoological Laboratory of the Museum of com- 

 pnrat ive Zoology at Harvard College, No. 299. This work was done at the Scripps 

 Institution for Biological Research, La Jolla, California to the staff of which 

 I wish to express mj- thanks for many courtesies shown me. 



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