The relation of nucleoli to chromosomes in the egg of Cribrella sanguineolenta etc. 397 
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forraer case a nucleolar remnant frequently persists for a langer or shorter 
time, in the latter no remnant is left. Moreover, in Cribrella tliese nucle- 
olar buds are spheric whereas in Ecliinaster the originally spheric frag- 
ments become four-lobed or quadripartite bodies. The striking structu- 
ral similarity of the latter to tetrads seemed to indicate that they might 
Fig. 4. 
Oöcyte near the cnlmination of the growth period showing the disposition of the nucleolar buds and 
the forming chromosomes (beaded threads) in the finely granulär nucleus. Two buds (secondary or 
accessory nucleoli) are seen in process of extrusion from the primary (chief) nucleolus. Stain, iron- 
hematoxylin. The alveolar cytoplasm appears gray, the nucleus pale blue and the nucleoli and 
chromosomes black (green in Auerbach's stain). X HO. 
be chromosomes, an Interpretation which appears the less warranted in 
the light of what may be learned from Cribrella. However, the fact that 
they cannot themselves be proved chromosomes does not in any way 
invalidate the conclusion that the chromatic substance of the chromo- 
somes comes from these bodies and thus in the last analysis from the pri- 
mary nucleolus. 
Very interesting is the fact of a generic difference between the eggs 
of Cribrella and Echinaster, in other respects very similar, as seen in the 
Archiv f. Zellforschung. V. 26 
