67 
’08), but consists of the entire chromatin content of an oöcyte nu- 
cleus. Because of its constitution and fate this body has been named 
the ‘ keimbahn-chromatin ’. 
(2) The history of the keimbahn-chromatin in Copidosoma is as 
follows: the chromatin within the nucleus of the young oöcytes seems 
to form a spireme which breaks up into chromosomes (Fig. 2); these 
chromosomes appéar to unite in pairs at or near their ends and are 
then drawn upon an asterless spindle Fig. 5): this spindle does not 
proceed to divide the chromatin, forming two daughter nuclei, but 
gradually contracts and condenses until it becomes an almost spheri- 
cal mass of chromatin (Figs. 7, 9, 10, 11, 12, 13, 15); this keimbahn- 
chromatin becomes situated near the posterior pole of the egg and 
is recognizable as the ‘nucleolo’ of SILvEsTRI. 
(3) The nucleus of the fully developed egg seems to arise in the 
following manner: oöcytes fuse end to end in pairs; the posterior 
member is the older and contains the keimbahn-chromatin only; the 
anterior oöcyte of the pair possesses a spindle which breaks down 
and transforms into a resting nucleus. Thus every egg of Copidosoma 
consists of two oöcytes which have united end to end (Figs. 15, 16, 
17,518). 
Ann Arbor, Mich. Feb. 2, 1914. (Eingegangen am 23. Februar.) 
Literature. 
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Arch. f. Zellforsch. Bd. 6. 1911. 
Boveri, T., Ergebnisse über die Konstitution der chromatischen Substanz des 
Zellkerns. Jena, 1904. 
Boveri, T., Protoplasmadifferenzierung als auslösender Faktor für Kernver- 
schiedenheit. S.-B. phys.-Med. Ges. Würzb. 1904. 
Bucuner, P., Keimbahn und Ovogenese von Sagitta. Anat. Anz. Bd. 35. 1910. 
BuouneEr, P., Die Schicksale des Keimplasmas der Sagitten in Reifung, Be- 
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wic, Bd. I. Jena 1910. 
DEBAISIEUX, P., Les débuts de l’ovogenese dans le Dytiscus marginalis. La 
Cellule T. 25. 1909. 
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Bd. 35. 1909. 
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gitta. 1. Die Entwickelung der Eier. Biol. Zeit. Vol. 1. 1910. 
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