102 BOTANICAL GAZETTE [august 



turn, but lies parallel to the blepharoplast for 0.44 of a turn, so 

 that the entire spermatozoid makes 1.66 turns. In all of the 

 spermatozoids examined the direction of coiling is the same — from 

 right to left beginning at the innermost end of the blepharoplast 

 when the side of the cell containing the latter is turned toward the 

 observer. 



After escape from the antheridium the larger or posterior portion 

 of the nucleus becomes extended and somewhat flattened. Both 

 nucleus and cytoplasm absorb water and show decided enlarge- 

 ment, the cytoplasm, especially in the posterior portion of the 

 spermatozoid, becoming very coarse and foamy through the great 

 enlargement of the vacuoles. Such a mature spermatozoid fixed 

 in the swimming condition over osmic fumes is represented in fig. 

 30. Exclusive of the cilia it has a length of 19. 7 M. 



Discussion 



morph 



Strasburger, Webber 



that 



reference to the additional evidence afforded by Equisetum without 

 risk, or even necessity, of a certain amount of repetition. In the 

 foregoing historical resume it was seen that the central point of the 

 discussion has been the question of the possible morphological 

 identity of the centrosome and the blepharoplast. Any analysis 

 of the relationship existing between these two structures must 

 include a consideration of the centrosome as found elsewhere in the 

 plant kingdom, and since it has to do with a cell problem of general 



phenomena 



spermato 



centrosomes 



covered by Butschli (10) in the diatom Surirella. It had earlier 

 been seen by Smith (77), who, however, did not recognize its true 

 nature and termed it the "germinal dot." A full account of this 

 centrosome was given by Lauterborn (59) in his magnificent work 

 on the diatoms, and later by Karsten (57). It lies near the nu- 

 cleus, becomes surrounded by radiations, divides and forms the 

 central spindle of the karyokinetic figure in a very peculiar manner. 



