McAllister . — Nuclear Division in Tetraspora lubrica. 693 
Summary. 
1. The nucleus of Tetraspora in the resting condition has a chromatic 
reticulum, net knots and nucleole distributed in the same manner as in the 
higher plants. 
3. A definite spireme is formed from the reticulum. The spireme 
segments to form about thirteen chromosomes. 
3. The nucleole shows no signs of disintegration until the increase in 
chromatic material has come to an end. 
4. Centrosomes are not to be identified at any stage of the nuclear 
division. 
5. Cell-division is accomplished by the splitting of a granular cell- 
plate which has been formed by the central spindle. The splitting takes 
place from the centre outward. 
6. The entire pyrenoid segments to form several starch bodies. No 
differentiated central area is present. 
University of Texas, 
February 15, 1913. 
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