310 WILSON GEE 



persistently open. Some manifestations of individual idiosyn- 

 crasies were observed among the specimens, since a few of them 

 were closed sometimes, even in spite of the daylight. How- 

 ever, these cases were so rare in occurrence as to make them of 

 negligible significance. Even the most closely contracted speci- 

 men, however, could be opened under the influence of a light 

 intensity of 32 candle power. This was tried upon a whole dish 

 of a couple of dozens of specimens which had contracted from 

 the effects of darkness, and by shifting the light every indi- 

 vidual was caused to expand fully, some of the more persis- 

 tently closed ones requiring from a half-hour to an hour of 

 exposure. 



This species of anemone is brightly colored; the disk may 

 be a greenish white to green, or even a brown or pink, the ten- 

 tacles partaking of much the same color. Torrey (1906) says 

 in regard to this color: "The characteristic green color of the 

 species is found only in individuals exposed to the sun. It is 

 due to the presence of a unicellular alga in the endoderm of 

 the column wall, mesenteries and tentacles. Where sunlight 

 does not penetrate, as under wharves (Calkins), or in caves, 

 the algae, though present, do not develop so luxuriantly as in 

 the more exposed situations, and the polyps are correspond- 

 ingly pale." It may be that in the relations of the alga to the 

 anemone we have the explanation of its apparently exceptional 

 behavior to light. 



In order to test the possible persistence of rhythms, both 

 tidal and diurnal, a half dozen specimens were kept for five 

 days under both constant dark and constant light. A second 

 series of experiments was conducted with this same end in view, 

 and these two dozen specimens showed so far as I was able to 

 determine, no impressed rhythmical behavior. Observations 

 were made at intervals of three or four hours usually, and from 

 eight o'clock in the morning to eleven o'clock in the evening. 

 Under constant darkness, in the first experiment made, except 

 for the expansion of an occasional specimen for a few hours, 

 the individuals remained persistently closed for over a week. 

 After this time there were decidedly irregular periods of con- 

 traction and expansion. Specimens kept under constant light 

 showed a uniform continuation of the expanded condition, con- 

 tracting only on the sixth day, and then as the result of an in- 



