The results from the present study also suggest that these cellular rearrangements are controlled by active cell movements and behavioral responses that include but are not limited to selective cell adhesion. Wilson, represents an extreme version of morphogenetic processes that normally go on continuously within intact sponges. These observations suggest that the experimental phenomenon of sponge cell-reaggregation and reconstitution, discovered by H. These choanocyte chambers interacted with pinacocytes and mesohyl cells to form excurrent canals, which continuously moved, fused with, and branched from one another. Choanocytes were never observed to undergo independent locomotion but were always found grouped together in choanocyte chambers. The locomotion of the pinacocytes varied according to position: those along the outer sponge margins were most active, whereas those in other parts of the surface moved relatively little. The choanocyte then transforms into an amoeba-shaped cell called a carrier cell, which gives up the spermatozoan to an egg, lying near a chamber formed by choanocytes and containing long lashlike appendages called flagella. Mesohyl cell locomotion was often accompanied by displacements of spicules, canals, and choanocyte chambers the patterns of these displacements suggested that the mesohyl cells were providing the motive forces for these rearrangements. specialized flagellated cell called a choanocyte, or collar cell, in another sponge. The most motile were the mesohyl cells, with many moving as fast as one cell-length per minute (15 microns/min). The shape and appearance of the sponges anatomical structures often changed substantially within a few hours. Each of the three main cell types (pinacocytes, mesohyl cells, and choanocytes) continuously moved and rearranged themselves so that the internal anatomy of the sponge was continuously remodeled. \): (a) Clathrina clathrus belongs to class Calcarea, (b) Staurocalyptus spp.Time-lapse cinemicrography was used to record the active movements of cells in living intact sponges.
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