Intramacronucleata is a subphylum of
ciliates. The group is characterized by the manner in which division of the
macronucleus is accomplished during
binary fission of the cell. In ciliates of this subphylum, division of the macronucleus is achieved by the action of
microtubules which are assembled inside the macronucleus itself. This is in contrast to
heterotrich ciliates of the subphylum
Postciliodesmatophora, in which division of the macronucleus relies on microtubules formed outside the macronuclear envelope.
Cavalier-Smith, T. (2003). "Protist phylogeny and the high-level classification of Protozoa". Eur. J. Protistol. 39 (4): 338–348.
doi:
10.1078/0932-4739-00002.