Sponges settling on solid substrates which are separated by sediment bottoms compete for the limited space. Some species have solved this problem by occurring as epizoans, thus avoiding the risk of being expelled from the habitat. The supporting species on the other hand, are specialized in that they possess skeletogenous ectosomal structures and aquiferous processes to maintain their integrity and to escape starvation or suffocation. Although specimens are sometimes intimately interwoven no chimaerid mixing of tissues was observed.