230 GERM-CELL CYCLE IN ANIMALS 
granulated protoplasm, an opinion concurred in by 
Hasper (1911), who terms it “Keimbahnplasma.” 
The similar material in Miastor metraloas, the 
“polares Plasma,’ is considered a special sort of 
protoplasm by Kahle (1908), and I can confirm this 
for Miastor americana. Further evidence of the 
protoplasmic nature of the substances which be- 
come segregated in the primordial germ cells is fur- 
nished by Boveri’s experiments on Ascaris. In 
1904 this investigator concluded from a study of 
dispermic eggs that the diminution process is con- 
trolled by the cytoplasm and not by an intrinsic prop- 
erty of the chromosomes, and that the chromosomes 
of nuclei lying in the vegetative cytoplasm remain 
intact, whereas those of nuclei embedded in the 
animal cytoplasm undergo diminution. This con- 
clusion has been strengthened by more recent experi- 
mental evidence (Boveri, 1910) both from observa- 
tion on the development of dispermic eggs and 
from a study of centrifuged eggs (see p. 178, Fig. 
53). Boveri’s results furnish a remarkable confirma- 
tion of the conclusions reached by the writer from a 
morphological study of the germ cells of chrysomelid 
beetles and expressed in the following words: “All 
the cleavage nuclei in the eggs of the above-named 
beetles (Calligrapha multipunctata, etc.) are poten- 
tially alike until in their migration toward the periph- 
ery they reach the ‘keimhautblastem.’ Then those 
which chance to encounter the granules of the pole- 
disc are differentiated by their environment, 7.e., the 
granules, into germ cells; all the other cleavage 
