Relationships between cell size and nuclear morphology in crayfish neurons

The morphology and ultrastructure of cell nuclei in neurons of the third abdominal ganglion of crayfish were studied from alternating series of ultrathin and semithin sections. The ganglion contains approximately 850 neurons with sizes between 10 and 200 mum. Cell nuclei show a great variability. Their size, the chromatin distribution, the number of nuclear pores, the degree of nucleolar segregation and the size of nucleolus vary in close relationships with the cell size.