312 WILSON GEE 



from the direct action of the light rays. There seems to be indi- 

 cated no persistence of rhythm in this species, either tidal or 

 diurnal. The specimens from which these data were derived, 

 however, were secured from Baker's Beach, San Francisco Bay, 

 and while this location is only a short distance removed from the 

 Golden Gate and the open sea, still the specimens here do not 

 get the full effects of the tides as experienced along the unpro- 

 tected ocean front. For this reason the evidence may be in- 

 sufficient to state positively that tidal rhythms are not estab- 

 lished in Cribrina as was found by Bohn (1907) in his work on 

 several species of anemones. However, the evidence does lead 

 one to the conclusion that the contraction and expansion in 

 this species is largely the result of the direct action of the sun's 

 rays, due perhaps to the symbiotic relation of the algae con- 

 tained in the cells of the body of this species of anemone. The 

 higher temperatures, desiccation, toxic solutions of sea water, 

 and such factors are effective also in producing contraction, as 

 was found by Bohn in his experiments on sea anemones. 



FEEDING REACTIONS 



Parker (1896) found in Metridium by feeding alternate pieces 

 of meat and filter paper soaked in meat juice to the tentacles 

 of one side of the disk, after a few times, the filter paper was 

 refused, though the meat continued to be accepted. Finally, 

 the tentacles of that side of the disk refused the meat also, but 

 when this was offered to the tentacles of the opposite side, they 

 accepted both the meat and soaked filter paper like the side 

 first fed. In accounting for this behavior, Parker (1896) says: 

 " The successive application of- a very weak stimulus is accom- 

 panied, not by. the summation of the effects of stimulation, but 

 by a gradual decline in these effects till finally the response 

 fails entirely." 



Jennings (1905) found in Aiptasia that refusal of the filter 

 paper was caused more rapidly by feeding meat alone for several 

 times than by feeding successively filter paper alone or alter- 

 nately filter paper and meat. He fed specimens of this genus 

 several pieces of crab meat in succession to the tentacles of the 

 left side only. When these tentacles became irresponsive, the 

 meat was offered to the tentacles of the right side and these 

 immediately accepted it. After a short period, meat was again 



