28O OTTO GLASER. 



strictly comparable conditions. It will be recalled that Chambers 

 "pierced the surrounding jelly with a needle." He did this in 

 order that "the egg to be measured could be held suspended in 

 the middle of the drop," hanging by one point from the ceiling of 

 his moist chamber. Inasmuch as the starfish egg is "soft;" the 

 jelly attached to the vitelline membrane; and this, prior to 

 fertilization, to the plasma surface, the egg if distorted would, of 

 course, approach a cylindrical form. Under the conditions des- 

 cribed by Chambers, the observer would look lengthwise along 

 the cylinder, and since the egg "rounds up" on fertilization, it 

 follows that the initial measurement might be the diameter of a 

 cylindroid and the final one that of a sphere. The second value 

 should be greater than the first. But Chambers reports an 

 immediate equality. One of two things then must have been 

 true: either his eggs were not distorted or the effect on the 

 diameters produced by the change in shape was compensated by a 

 loss in volume. 



What is the likelihood that his eggs were distorted? It seems 

 to me considerable for even the Arbacia egg under similar 

 circumstances gives no indication of a decrease in diameter. 



For these particular observations I selected eggs suspended 

 from a single point. The measurements therefore were made 

 under the conditions stipulated by Chambers. If now there is 

 cylindroid distortion before fertilization, the "rounding up" 

 process which incidentally the Arbacia egg also exhibits- 

 should give us a second measurement no smaller and possibly 

 even larger than the first. The values recorded in Table III. 

 speak for themselves. 



TABLE III. 



DIAMETERS OF EGGS. 

 Suspended at One Point. 



Egg. Unfertilized. Fertilized. 



1 76. 3 M 76.9 M 



2 72.3 72.5 



3 75-7 76.0 

 4 73-5 74-2 



5 72.9 74-2 



6 74-4 74-2 



Average: 74.2 ^ 74.7 M 



