JOHNSON. — Nuclear Division 
PLATE I. 
Figs. 27-34 are all from the serosa. 
Fig. 27. A cell undergoing division by formation of a cell plate. The daughter 
nuclei are still united by a connecting thread. The dotted line on the 
left indicates the edge of the fragment of membrane in which this 
cell occurs. From the serosa of an advanced embryo. X 304. 
Fig. 28. A cell divided by constriction, without the formation of a cell plate. The 
nuclei have undergone degeneration. From the serosa of an advanced 
embryo. X 150. 
Fig. 29. A cell, the nucleus of which has undergone tripartite division. From an 
old serosa. X 150. 
Fig. 30. Nucleus of the same, more highly magnified. The chromatin is grouped 
in granular masses. Two of the daughter nuclei are still united by 
strands of the nuclear membrane. X 680. 
Figs. 81-32. Constricted nuclei from a young serosa. One of the daughter nuclei 
of each is larger than its mate, and has itself become elongated and 
constricted. X 804. 
Fig. 83. Quadrinucleate cell. The upper of the two original nuclei has divided 
in a longitudinal, the lower in a transverse plane. Nucleus a still 
shows a remnant of the connecting thread, and nucleus b retains the 
conical form it had in division. Both nuclei have rotated 90° from 
the plane of elongation. X 804. 
Fig. 34. Cell from the serosa of a far advanced embryo. The nuclei have under- 
gone extreme degeneration. Each nucleus is surrounded by a bright 
ring, outside of which is a broad zone of a radiate structure, more 
stainable than the rest of the cytoplasm. X 150. 
