English: Diagram illustrating changes during conjugation of Colpidium colpoda.

M, Old meganucleus undergoing disintegration.

m, Micronucleus.

N, migratory, and

S, Stationary pairing-nucleus.

M′, M′, the new meganuclei, and

m′, The new micronuclei in the products of the first fission of each of the exconjugates; the continuous vertical line indicates period of fusion, its cessation, separation; dotted lines indicate fission; the spaces lettered 1-7 successive stages in the process; the clear circles indicate functionless nuclei which degenerate.