PLATE 3 



EXPLANATIOX OF FIGURES 



Cell shape and nuclear transformations 



Figures 17-36, X 165. Stain, methylene blue and eosin. 



All these drawings were taken from one-half of one-cross section of a queen 

 larva whose fat-cell nuclei were just in the act of dispersing their nuclear granules 

 into the cytoplasm. The black areas are those in which the nuclear granules were 

 stained by methylene blue, the stippled regions are the areas of dense nucleo- 

 cytoplasmic trabeculae through which the granules are dispersing from the nuclei; 

 this stains deeply red with eosin. The clear areas are the regions of lighter 

 stained cj'toplasm containing fat-vacuoles. 



This plate is designed to show the relations of these three regions in the cells 

 of this stage; to demonstrate the relation between their disposition and the cells' 

 shape, and to present evidence bearing on the mechanics of the process of nuclear 

 extravasation and dispersal of basophile granules. Only those cells were drawn 

 which appeared to be cut almost exactly through the median plane of the nucleus, 

 and in the plane of greatest nuclear extravasation, through other trabeculae than 

 those figured of course extended above and below the plane of the section. 



In figures 17-21 are indicated variations from the bipolar to the tripolar 

 type of cell; in figures 22-25 from bipolar to hexapolar; in figures 27-31, from 

 bipolar to asymmetrical tripolar, or possibly multipolar, and in figures 32-36 

 variations from bipolar to tetrapolar cells. Each cell exhibits that type of 

 nuclear distortion which will most effectively distribute the nuclear granules 

 throughout the cytoplasm of a cell of that particular shape. 



Comparing figure 3, plate 1, which is of a cell before this stage, but shows the 

 beginnings of it, it is apparent that the central cytoplasm and nucleus both assume 

 approximately the shape of the cell outline even before the fat-vacuoles approach 

 the nucleus. This may be considered a predisposing factor in directing the tra- 

 beculae later, and may be taken to indicate incidentally that nucleoplasm and cyto- 

 plasm are so little different in density or consistency that the distortion by fat- 

 vacuoles affects the former against whatever surface tension the nuclear membrane 

 may exhibit, tending to form the nucleus into a sphere. When the fat-vacuoles 

 later move toward the nucleus, and the larger of these press in through the central 

 cytoplasm toward the vesicle, they may be the active agents in pressing the 

 nuclear mass further out of shape; their effect is presumably augmented, however, 

 by a centripetal tendency on the part of the larger nuclear granules. Both these 

 forces seem to be occasioned by the cessation of larval nutrition, and their nature 

 is not clear. It is fairly certain that the nucleoplasm itself does not disperse 

 with the granules, from evidence of the staining reaction of the granules them- 

 selves as they pass into the cytoplasm. The dispersing forces must lie in the 

 granules themselves, conceivably a like static charge, for instance. 



