142 VARIATION IN THE NUMBER OF STRIPES 



times not many days afterwards diglyphic forms are numerous. White lines lead 

 from the margins of the oral opening to the directive tentacles. This fact makes the 

 directives easy of determination aside from the fact that their length is greater and 

 that they are situated at the angles of the mouth. Division usually takes place in 

 less than twenty-four hours and proceeds more rapidly in confinement if the indi- 

 vidual is exposed to the air for a time and then covered with fresh sea-water in imi- 

 tation of exposure to air and water occasioned by the tide. Division is very apt to 

 be accomplished at night, but in two instances it was accomplished within a few hours 

 during an afternoon. In nature it seems probable that division is accomplished 

 during high tide only, for during low tide, while exposed to the air, the animal con- 

 tracts and is not infrequently covered with an envelope of slime. At such a time it 

 remains apparently quiescent. 



Experiments were made to see if it is possible to delay or prevent the completion 

 of division when once begun. Three individuals that showed evident and equal 

 constrictions were chosen. Two of them were gorged with food, while one was not 

 fed. The unfed individual completed its division in the normal time. The other 

 two lost outward signs of constriction and spent twelve to fourteen hours digesting 

 their meal. One began three days later to divide again, but the other showed no 

 such tendency after two weeks. 



Two individuals were divided each into two parts by a longitudinal cut to see 

 if the resulting parts would regenerate or become normal individuals. One anemone 

 was cut as nearly as possible into halves. When first cut the halves drew over so 

 as to press the cut edge to the surface of support only in a little greater degree than 

 do recently self-divided individuals. By the following morning both parts had the 

 cut edges rolled in toward the central axis a condition observed for self-divided 

 individuals (Figs. 3, 4, 5, 6, 7). From one side of another individual only a small 

 fragment was shaved. After twelve hours this one seemed to be a perfectly normal 

 individual, and even the fragment after a few days had rounded itself up into the 

 shape of a very small half-contracted anemone and possessed a few short tentacles. 

 Three days later this fragment showed external evidences of seven mesenteries and 

 had one orange stripe. Three days later seven more mesenteries and two orange 

 stripes were evident. In nature one frequently finds a large anemone surrounded 

 by a number of small individuals. The latter, I believe, are produced by basal 

 fragmentation. 



A few cases of tryglyphic individuals were observed. In one case eighteen (Fig. 

 8) and in another fourteen stripes were noted. In such individuals I have not had 

 the good fortune to observe division. 



