266 l'iii)u rsihf of CaJifdyiiia }'t(l)licntioiis in Zooloi/n [Voi,. 10 



were late in ti'aiisroi-iiiinir. they may liavo ('ntlai:ct'llatt'(l ai;ain. they may 

 liave been Hajrellates all of the time, or tluy may have eome from some 

 of the amoebas transferred to tlie flagellate cover, for it i.s impossible 

 to get a preparation entirely free from them because there are always 

 a few left at the two snrfaces of the original preparation and the 

 poured-oflf liquid must necessarily have a few in it. From which it will 

 be seen that the exact duration cannot be ascertained, but it is between 

 ten and twenty- four hours. 



Not only docs a llaj^cllate turn back to an ainocha in the ordinary 

 course of its life, but it may be stimulated to do so at any time during 

 its flagellated state. This has been done by raising or by lowering the 

 temperature slightly, and by ineelianical disturbance. 



After a stimulus has been applied, the flagellate innncdiatcly begins 

 to whirl about until it seems exhausted, when it settles to the bottom 

 and a.ssumes its amoeboid motions. The flagella are present for a time 

 and remain in motion, but they are found to extend from any jiart of 

 the body, front, back or side (pi. 22, figs. 100-103; pi. 23. figs. 120, 

 122), but still with the nucleus near their base. If a temperature 

 stimulus is used and is removed in a few minutes, normal swimming is 

 resumed, liut if it is left during the whole time, exflagellation continues. 

 After two hours most of the individuals may be amoebas. 



After aii>- iiii'cliaiiien! stiimihis. such as pouring the liquid contain- 

 ing the (lagellales on to another coN'ei- (which may also be done without 

 causing a great disturbancel, by touching the medium with the micro- 

 scope ob,icctive, by the addition of fresh medium added so that the 

 water of the preparation is stirred up. or after temperature change, 

 the flagellates become sticky. In whirling about they run into each 

 other and it is with difficulty that they become separated. They may 

 settle down together but they do not copulate or conjugate as might be 

 expected, for in the first place small clumps are soon found, and also 

 when followed up this sticky condition has no further ajipcarance of 

 reproductive signitii'anee, but seems to be merely a reaction to un- 

 favorable conditions. 



The sticky condition of the extlagellafing individuals may last only 

 a short time or it may persist until clumps of from feu- to many indi- 

 viduals may be found (pi. 23, tigs. llo-118, 121. 12+-1261 which are 

 in the amoeboid stage. The.se move over and over each other, seeming 

 to be unable "to get out of touch" with each other. 



Material at room temperature does not agglomerate as often as it 

 does at a lower one. Flagellates put in a refrigerator were invariably 



