Conjugation 

It is the temoorary pairing of two individual of the same species but of two different mating types. In this process, two individuals come together and attach themselves by their ventral surface. These two individual are called as conjugation. Before entering into actual process, they become sluggish. At the point of contact, the pellicle is dissolved and the cytoplasm of both the conjugant becomes continuous. In the process, the macronucleus degenerate and the micronucleus divides twice to form four micronuclei; out of the four micronuclei, three degenerate and the remaining one divides unequally to form a large female nuclei and a small male nuclei. The migratory nuclei of both the conjugation are exchanged so that the male nuclei of one passes into the other and fuses with the zygote nucleus (synkaryon). Thereafter, both the conjugation get separated and are called as exconjugants. The synkaryon nucleus divides successively into two, four and eight nuclei. Out of the eight nuclei, four become the macronucleus and three out of the remaining four degenerate and the remaining one acts as micronucleus. Now each exconjugant divides  in to two by transverse fission to form four paramecia, each having a single micronuclei and a macronuclei. Each daughter paramecia may divide further to form eight daughter paramecia.
female nuclei forming the

Signification. Conjugation is an important phenomenon in the life of Paramecium. It serves as a process of rejuvenation and reorganisation by which the vitality is restored. It combines the genetic material of two individuals of different mating types that resultsin increased vigour of the offspring.