Plate XXIII 



Segmentation of the egg of Miastor americanus, after HF.GNER (1914). 



1, two segmentation nuclei (<.".#.), dividing polar nucleus (/..), polar plasma 



(germ-cell determiner, p.p.}, and group of nurse-cells (n.c.). 



2, rather later stage with one primordial germ-cell (p.g.c.}, nuclei undergoing 



chromatin-diminution (r.m.), and clumps of cast-out chromatin (c.r.). 



3, 4, early and later blastoderm stages with two and four primordial germ-cells. 



