65 
melid eggs has been pointed out in a previous communication (HE6NER, 
’09); in Saarrra, Bucuyer, (09, ’10) has described as ‘ Keimbahn- 
chromidien’ the ‘besondere Körper’ of Erparıewsky (’09, ’10); and 
Kian (11, ’13) has shown that the keimbahn-determinants in the eggs 
of certain Cladocera consist of chromatin from the nurse-cell nuclei. 
In part II of the present series of ‘Studies on Germ Cells’ I have 
considered at some length the origin, nature, fate, and significance 
of the keimbahn-determinants. The conclusions have been reached 
that these bodies may arise from nucleoli (metanucleoli), chromatin 
(chromidia), yolk, mitochondria, and metabolic products, or may 
represent differentiated portions of the cytoplasm. It was further 
concluded ‘that every one of the eggs in which keimbahn-determinants 
have been described consists essentially of a fundamental ground sub- 
stance which determines the orientation; that the time of appearance 
of keimbahn-determinants depends upon the precociousness of the egg; 
that the keimbahn-determinants are the visible evidences of differ- 
entiations in the cytoplasm; and that these differentiated portions of 
the cytoplasm are definitely localized by cytoplasmic movements, 
especially at about the time of maturation. ’ 
Copidosoma represents one of the very few cases in which it 
is possible to determine with certainty the origin of the keimbahn- 
determinants; any statement regarding the general significance of 
these bodies may therefore seem premature. It may, however, be 
pointed out that the history of the keimbahn-chromatin in Copidosoma 
indicates a more important function than that ascribed to keimbahn- 
determinants in the above quoted conclusions. 
The origin of the nucleus in the eggs of Copidosoma could not 
be determined so accurately as that of the keimbahn-chromatin. 
Three hypotheses have been considered; the first may be dismissed 
with a few words, i. e., formation de novo. This method has been 
maintained by several investigators within recent years, but the evi- 
dence has not gained many adherents. The second hypothesis is this: 
when the oöcyte nucleus breaks down to form the spindle (Fig. 5) 
chromatin granules may be cast out into the cytoplasm as is known 
to occur during the maturation processes in many animal eggs. These 
granules may be so small that they are invisible during most of 
the growth period. They become visible again shortly before the egg 
is ready to be laid when they accumulate to form larger masses of 
chromatin which are incorporated within a nuclear membrane near 
Anat. Anz. Bd. 46. Aufsätze. 5 
