56 GARY N. CALKINS. 



the ten drops of hay infusion medium. On the seventh d.iy the 

 monster had grown enormously ' Fig. 17, c ); on the ninth day it 

 gave rise to a small free cell which \\as an exact miniature copy 

 of the original cut fragment (17, e). This cell arose from the 

 upper end of the monster as shown in 17, d. On the tenth day 

 the isolated fragment was killed for the determination of the 

 nuclear apparatus and was found to have a normal full size 

 macronucleus. On this day also, the monster divided at the 

 point .v forming two monsters, one having three mouths (17, g) 

 the other with only two (17, /), but the latter at the time of 

 division, was also dividing to form a small terminal deformed cell. 

 Thus two divisions were going on at the same time in the proto- 

 plasmic mass. The small deformed cell was detached from the 

 parent monster on the same day and appeared as a minute 

 reversed duplicate of the original fragment (Fig. 17, //). This, 

 like the first detached fragment, had a single contractile vacuole. 

 On the eleventh day the small fragment was still alive and active 

 but had not regenerated nor grown in size while the two monsters 

 had grown to look more like paramecia fused (17, i and j). On 

 the twelfth day the small fragment was dead while the others 

 remained as before. On the thirteenth day the smaller monster 

 had grown much weaker and was killed on the eighteenth of 

 February or the fourteenth day (17, k). The remaining monster 

 was very plastic changing shape from day to day until on the 

 twenty-fourth of February appearing very weak, it was killed, 

 twenty days after the original operation during which time no 

 more than three mouths were formed in this part of the divided 

 monster. The original fragment thus developed seven mouths 

 indicating at least seven attempts to divide while the monster 

 divided once to form two monsters. Preparations (17, k and /) 

 show relatively enormous nuclear masses. 



One interesting feature of this experiment was the form. it ion 

 of free-living but abnormal fragments separated off from the 

 protoplasmic mass. In experiments nos. 22 and 25 (Table II.) 

 the mon-trrs gave rise to similar cells either attached (22) or 

 free (25), but in ever) case the^e offshoots were normal in struc- 

 ture although abnormal and weak in function. 



In No. 22 the cell was cut in /one II. as shown in Fig. 16, a, 



