386 TRANSACTIONS AND PROCEEDINGS OF [Sess. lyi, 



the stages of the formation of the primary endosperm-nucleus 

 gradually backwards to the best of my ability. 



The nucleolus of fig. 40 contains a number of spherical 

 endonucleoli, perhaps arranged as the beads of a rosary. 

 Those endonucleoli marked with an x seemed to touch one 

 another, although they were lying at different levels, while the 

 uncrossed areas were placed so deeply that I could not con- 

 vince myself definitely as to whether they formed a chain or 

 not. This one nucleolus cost me three days hard work, as 

 sketches of the endonucleoli had to be made again and again, 

 after revolving the stage, changing the light, &c., &c. 



The nucleolus, fig. 39, is surrounded by a nucleolar mem- 

 brane which seems to be bulging out at the micropylar end, 

 and leading apj)arently to the directing bodies {dir. h.). 

 Several larger and smaller endonucleoli are arranged in a 

 line across the nucleolus. 



Figs. 38, 37, show respectively four small and one large, 

 and four small and two large, endonucleoli. 



In fig. 36^, illustrating the act of conjugation of the two 

 nucleoli, both of these are seen to be enclosed by a mem- 

 brane. The micropylar nucleolus contains two large endo- 

 nucleoli embedded in nucleoloplasm which has a mottled 

 appearance, while the antipodal nucleolus shows an indistinct 

 spongy appearance. 



In fig. 36*^ both nucleoli have nucleolar membranes ; the 

 micropylar one contains three, and the antipodal one contains 

 nine endonucleoli. 



The nucleoli in fig. 35 show again a set of peripheral 

 small endonucleoli, and, respectively, one and two excentrally 

 placed large endonucleoh. 



Figs. 34, 33, 32 show large nucleoli with ill-defined 

 endonucleoli. 



We learn thus from figs. 9'\ 11, 13% 13'', 14, 31, 35, 41-47, 

 that the nucleolus possesses a very complicated structure, 

 and I have endeavoured to bring the details together revealed 

 by the difierent nucleoli, nuclei, and cell-plasmata, and have 

 constructed fig. 48 to illustrate my conception of the acliro- 

 matin of a normal highly-developed cell. 



A cell may Ije divided into three zones — a nucleolar or 

 intra-nuclear (0), a nuclear (4-), and an extra-nuclear (2) 

 zone, which latter forms the " body " of the cell. These 



