1899] OOGENESIS I1N PINUS 279 
mental history. New support is thus given to the theory that 
the ventral canal cell is the homologue of the egg. 
2, In the development of the oosphere nucleus the chro- 
matin takes the form of nucleoli which finally collect from all 
parts of the nucleus to a definite area near the center and there 
develop into a typical spirem. The linin often stains like chro- 
matin, 
3. After the male pronucleus is within the oosphere nucleus, 
the chromatin of the two pronuclei appears as two distinct masses 
inthe spirem stage. Perhaps segmentation of the two spirems 
occurs while they are still separate. 
4. Although centrosomes were not positively identified in 
ay part of the work, appearances favor the supposition that they 
may accompany the male nuclei. 
5. The fate of the spindle indicates that the kinoplasmic 
fibers arise through a transformation of the cytoplasmic reticulum. 
THE UNIVERSITY oF CHICAGO. 
EXPLANATION OF PLATES IV-VI. 
A Zeiss 2m : ; ; ee ‘ 
Zeiss 2™ apochromatic homogeneous immersion objective and compen 
8 cular no. 4, with camera lucida, were used for all drawings except 
bt a. 45 (comp. oc. no, 18) and the outline sketches 9, 794, 244, 25% 
chit “74, which were made with low power dry lenses. All drawings 
uced one half in photo-engraving. 
Plantain “ #. 0., nucleus of oosphere; 7. v., nucleus of ventral canal 
cell, Fed vacuole ; s., portion of spindle; v., remains of ventral canal 
bs : “9 ie of central cell before cutting off the ventral canal cell. 
Pies, : utting off of the ventral canal cell. 
Pa 6 , . 5. Three views of the ventral canal cell. ia 
toles and eae of the oosphere, showing nucleus of oosphere, protel 
Fig.7. & ventral canal cell. ao 
the Ducleus Segal large ventral canal cell and spindle connecting It 
Fig, g a the oosphere. 
wn, | ans he wall between ventral canal cell and oosphere has es 
ia NM the nucleus of the ventral cell free in the oosphere. Frag 
A pe Pindle Scattered through the oosphere. 
* Similar to the preceding, but more advanced. 
with 
