106 



GARY N. CALKINS 



no. 11 a small bud was formed in addition but this bud did not 

 develop. 



In experiments 16, 25 and 75, the cells were cut obliquely, no. 

 75 being a typical case. Here the cut passed through the pos- 

 terior end of the cell as shown in fig. 11. After 18 hours the ante- 



10 



It 



Fig. U) Experiment 12. Cell at the onset of division. Fragment A regenerated 

 in 18 hours. B divided in the original plane of division forming one minute cell 

 from the anterior end, and a perfect cell from the posterior end. 



Fig. 11 Experiment 75. Cell at the mid-phase of division, fragment A divided 

 in the original division plane into A' and A", the latter developed into a minute 

 but perfect cell in 24 hours, the former into a normal large cell. B formed a small 

 but perfect cell without a micronucleus (B below on right). A" represents the pos- 

 terior fragment of A 42 hours after cutting. 



rior part A had divided into a normal A' and a minute A", while 

 the posterior part B had regenerated into a perfect cell. After 

 42 hours A' and A" were nearly perfect and were killed for internal 

 structures. In experiment 25 three perfect cells were formed in 

 a similar manner, but in no. 16 one fragment (A) died before 24 

 hours. 



