Morphology and Physiology
Membranipora membranacea colonies consist of individual organisms called zooids, each with a chitinous exoskeleton which is secreted by the epidermis. This exoskeleton, hardened with calcium carbonate, is known as the zooecium, which not only serves to protect the internal structures of the organism, but also keeps the individual permanently attached to the substrate and neighboring zooids. Zooids within a colony can communicate via pores in their interconnecting walls, through which coelomic fluid can be exchanged.
The internal, living portion of the zooid is known as the polypide, whose walls are formed by the outer epidermis and inner peritoneum. The lophophore, a ring of ciliated tentacles, protrudes from the polypide to feed. When not feeding, the lophophore retracts into the polypide through the tentacular sheath. The lophophore is controlled by the zooids nervous system, which consists of a ganglion at the lophophore base. This ganglion is responsible for motor and sensory impulses to and from the lophophore, as well as the epithelium and digestive tract. The lophophore retractor is the muscle which controls the movement of the lophophore.
Unlike most byrozoans, this species does not have the ovicells or avicularia often seen in other members of this phylum.
Read more about this topic: Membranipora Membranacea
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