no THE AMERICAN MONTHLY [April 



This reiii.-ii'kaMc t'oi-in wms t'dUinl \t'iv aliniidaii t ami 

 was given prolonged stmly. In tlir acti\e riag-ellate 

 stage it mov(>(l ahonl in an easy niaiiin'f. i fvol \in;r on its 

 long axis: thf riauelluin Ikmii^" thrown into graceful 

 curves from its origin to its tlistal (MhI. After moving 

 about for an hour, more or less, the coming change to the 

 heliozoan stage was ushered in liy a slower movement, 

 an occassional lialt, slight trtMuors and the apjjearance 

 on the anterior body half of short, heavy and blnnt ten- 

 tacle-like processes, with a simultaneous contraction of 

 the body. 



If the en<lo]ilasm was well filled with tiie granules men- 

 tioned, the body would he modulated. The rays then 

 extended until as long as one or two of its diameters; 

 the tentacle-like processes covering the anterior half, 

 going to form the anterior lays; the tlagellum becomes 

 inactive and is coiled close to the body. In this state it 

 resembled very much a light cohered Heterophry Leidy. 

 changing its contour gradually nwd almost imj)ercept- 

 ably, l)ut never to any great extent. 



The change from the helio/.oan to the flagellate stage 

 is heralded by the gradual withdrawal of the rays, the 

 tiajiidluin uncoiling- au'l lia\ ino- a sliiiht mox'enient. a few 

 sliglit (|uivei's of the i)ody ami simultaneous elongatit)n 

 to tlie original shajie of the lla^ellate; the tlagellum be- 

 comes very active at once and the inrusorian darts off to 

 live foi an hour or so in this phase. Sonictimes the 

 original form is not restored entirely until it has moved 

 about for a xhort while, but in all cases observed the 

 original shape was finally assnined. 



Kach one of the phases of this dual life, as witnessed 

 by the writer occnpieil from fifteen minutes to one and a 

 half hours. 



While ill the helio/oan stage the manner of capturing 

 and eiigulphing food is identically the same as when per- 

 formed by the Actinophry sol. One form tliat was u^- 



