II. I 



CELL-DIVISION 



51 



A 



The length of the polar furrow varies directly with the size 

 of the drops which unite to form it; its direction makes an 

 angle with the plane separating the first two, which varies 



r -n I i 



FIG. 29. Arrangements of six oil-drops. In all cases A = B = a b. 

 In A, a = a", b' = b". In B, a > a", b' > b". In C, a' < a", b' < b". 

 J, first furrow ; II, second furrow. (From Korschelt and Heider, after 

 Roux.) 



FIG. 30. Various arrangements of eight oil-drops, all bilaterally 

 symmetrical about the first furrow (/). In all cases the first division has 

 been equal. In A and B the second division (//) has also been equal, 

 but in C a, b are smaller than A, B. In A, a", b", A", B" < a, b', A', B'. 

 In B and C, a", b" < a, b', but A", B" = A', B' ; hence a", b" < A", B". 

 (From Korschelt and Heider, after Roux.) 



A L 



Fro. 31. Arrangement of six (^1) and eight (B} oil-drops, after unequal 

 division of four equal drops (A = B = a = b), the smaller and larger 

 drops regularly alternating. (From Korschelt and Heider, after Roux.) 



E 2 



