Membranipora is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of bryozoan in the family Membraniporidae

Membraniporidae

Membraniporidae is a bryozoan family in the suborder Malacostega. Membranipora form encrusting or erect colonies; they are unilaminar or bilaminar and weakly to well-calcified. have vertical and basal calcified walls, but virtually no frontal calcified wall: most of the frontal surface is occupied...

. A typical example is the widely distributed species Membranipora membranacea

Membranipora membranacea

Membranipora membranacea is a very widely distributed species of marine bryozoan known from the Atlantic and Pacific Oceans, usually in temperate zone environments. This bryozoan is a colonial organism characterized by a thin, mat-like encrustation, white to gray in color...

that commonly encrusts seaweeds, particularly fronds of the kelp

Kelp

Kelps are large seaweeds belonging to the brown algae in the order Laminariales. There are about 30 different genera....

s Laminaria digitata, L. hyperborea, and Saccorhiza polyschides.

Colonies of M. membranacea show different forms of polyphenism

Polyphenism

A polyphenic trait is a trait for which multiple, discrete phenotypes can arise from a single genotype as a result of differing environmental conditions.-Definition:A polyphenism is a biological mechanism that causes a trait to be polyphenic...

 as spines, tower zooids, chimneys and stolons.

Reproduction

The eggs of M. membranipora develop into planktonic cyphonautic larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e which is strongly triangular in outline and about 850μm x 600μm big.