6 o6 MitrrilL—The Development of the Archegoninm 
resting nucleus like that of the egg. The membranes of the two nuclei are still 
intact. The changes in the two nuclei may be better described under later figures. 
In this case the stalk-cell lies near the second sperm-nucleus. 
Fig. 39. (x 1600.) The stalk-cell enlarged from the section represented in 
Fig. 38 to show its thick nuclear reticulum, and scanty vacuolate cytoplasm. 
Fig. 40. ( x 200.) This figure shows the first sperm-nucleus in contact with 
the egg-nucleuSj and the second sperm-nucleus almost touching its membrane. 
The sperm-cells entered the egg unusually far down on its side, and the bursting of 
the pollen-tube was sufficient to force them to this position near the egg-nucleus. 
This also accounts for the contact of the first sperm-nucleus at the side instead 
of the apex. The remains of the neck-cells could not be found. The egg- 
membrane did not close up again after the contents of the pollen-tube entered, as 
was the case in the egg represented in Fig. 36. 
Fig. 41. (x 400.) This represents a stage succeeding that shown in Fig. 37. 
The contents of the sperm-nucleus are losing their density, and numerous small 
spheres have appeared in the nuclear cavity. Crenate folds are observed in the 
membrane of the egg-nucleus at the surface of contact of the two nuclei. 
Fig. 42. (x 400.) The dense contents of the sperm-nucleus have disappeared 
except at the centre, and the nucleoli are larger and fewer in number. About the 
periphery of the sperm-nucleus a chromatic reticulum is seen. The chromatic 
contents of the egg-nucleus have begun to migrate to a point beneath the sperm- 
nucleus. 
Fig. 43. ( x 400.) The centre of the sperm-nucleus is quite free from chromatic 
contents. The peripheral reticulum shows larger collections of chromatin. 
Nearly all of the chromatin of the egg-nucleus has collected beneath the sperm- 
nucleus. The crenate folds in the nuclear membrane of the egg appear larger, 
particularly in the centre. 
Fig. 44. ( x 400.) The chromatin of the sperm seems to have moved nearer 
to that of the egg. The intervening membranes are preparing to break up. The 
egg-nucleus has constructed a chromatic reticulum. 
Fig. 45. (x 400.) The membranes have broken up, and the two nuclear 
cavities are continuous. Small spheres with granular contents now occupy the 
position formerly occupied by the membranes. The thick knotted chromatic 
threads of the two nuclei still remain distinct. All traces of nucleoli have disap¬ 
peared, and the contents of the nuclear cavity have become denser and more 
fibrous. At a few points, the miter nuclear membrane is disappearing, and the 
cytoplasm is encroaching on the nuclear cavity. 
Fig. 46. ( x 800.) A tri-polar spindle found near the apex of the egg in the 
position commonly occupied by the second sperm-nucleus. 
Fig. 47 . ( x 800.) Following Fig. 45, and showing the origin of the first 
segmentation-spindle, which arises between and among the two groups of 
chromatin. The spirems have mostly segmented at this stage, but the segments 
have not yet become homogeneous. The chromatin of the egg does not all appear 
in this section. A preparation showing the two groups of chromosomes to better 
advantage was injured so that it could not be satisfactorily figured. The spindle 
is at first multipolar, but soon becomes monaxial, the position of the poles 
apparently being determined by collections of a dense granular substance which 
takes a diffuse reddish stain with the Flemming combination. The contents of the 
