Ultrastructure of segmentation mitoses in cleaving newt eggs after blocking of centrospheres by quinoline.

In quinoline treated blastomeres of Triturus helveticus Raz. and Pleurodeles waltlii Michah., microtubules disappear and around the centrioles markedly enlarged dense bodies accompanied by striated bodies are accumulated, from prophase beyond metaphase. It is concluded that these bodies in untreated cells play a role in the formation of the spindle microtubules. - During metaphase the chromosome are smooth-surfaced and show a pronounced tendency to stickiness. During ana-telophase they become surrounded by nuclear membranes and form caryomeres. - Qinoline does not interfere with centriole replication, but prevents the separation if diplosomes that have been already formed, if it acts before that separation. - Some centrioles exhibit different degrees of ultrastructural disarrangement.