Séance is a community analysis pipeline for the 18S rRNA marker gene incorporating homopolymer modelling for clustering 454 data, phylogenetic placement and visualisation. Séance is distributed under the GPLv3 license (see COPYING) Installation instructions can be found in INSTALL and at: http://wasabiapp.org/software/seance/installing-seance/ Usage guidelines can be found at: http://wasabiapp.org/software/seance/using-seance/