158 BOTANICAL GAZETTE [march 



neck admits free access of water. The dome-shaped cell wall which 

 separated the egg cell from the ventral canal cell seems almost to 

 disappear at the time of the disorganization of the ventral canal 

 cell, so that the protoplast of the egg cell is exposed at the neck side to 

 the dilute slimy substance, but this exposed surface retains its irregu- 

 lar dome-shape. 



The cytoplasm of the egg cell has a fine fibrillar structure, very 

 dense around the nucleus and vacuolate toward the periphery of the 

 cell. The upper part of the nucleus becomes depressed, so that its 

 concave side is directed toward the neck, and it presents a crescent 

 form in the side view (figs. 48, 49). The chromatin material within 

 the nucleus becomes transformed completely into a system of anasto- 

 mosing and branching fine strands and small ragged clumps, charac- 

 teristic of the resting condition. One, two, or more small nucleoli 

 are present. 



Several sperms enter the neck of the archegonium and reach the sur- 

 face of the exposed protoplast of the egg cell at the so-called receptive 

 spot (fig. 50). Normally one of these sperms penetrates the cytoplasm 

 of the egg. The cytoplasmic layer which surrounds the egg nucleus 

 at this time is rather shallow on the exposed surface in the direction 

 of the neck, so that the sperm has to pass through only a shallow 

 layer of the cytoplasm. When the sperm reaches the nucleus, the 

 coil becomes shortened and the penetration of the sperm into the 

 nucleus begins from the anterior region, followed gradually by the 

 posterior region (fig. 57). 



During the penetration of the sperm the chromatin reticulum of 

 the egg nucleus persists as it was before, but a peculiar irregularity 

 of the reticulum is observed to have occurred near the intruding 

 sperm, which in penetrating has presumably caused a movement of 

 the contents of the egg nucleus. After the sperm has completely 

 penetrated into the egg nucleus, this disturbance of the homogenous 

 arrangement of the chromatin reticulum is still observed so long as 

 the sperm within the egg nucleus maintains its individual outline 

 (figs. 52a, b). 



It is also observed that there is present a clear region directly 

 surrounding the body of the sperm within the egg nucleus, and this 

 seems to be a transient stage preceding the disintegration of the body. 



