Bryozoan Vocabulary

For a comprehensive list, see

Morphology or Growth Form: Basic physical morphology (form or shape) of the colony. See morphology sheet for an explanation of common growth forms.

Endozone: The inner zone of a massive or erect colony, composed of thin-walled proximal zooecia

Exozone: The outer zone of the colony

Colony: Morphological and functional unit (structure) that acts as a complete organism. Consists of one or more physically connected zooids that are genetically uniform (Budded asexually from one larva).

  • Zooarium: The skeleton of the colony (zooecia and inter-zooecial spaces)

Zooid: One of the physically connected morphological units of which a colony is comprised

  • Autozooid: Feeding zooid.
  • Polymorph or Heterozooid: Zooid that differs distinctly in morphology and function from feeding zooids.
  • Mesopore or Mesozooid: space-filling polymorph in exozone between feeding zooecia.

Zooecium: The skeleton of a zooid (Calcareous)

  • Zooecial Aperture: terminal skeletal openings (perpendicular to zooidal growth direction. Described based on cross-sectional morphology. May be described as round, subround, polygonal, subpolygonal, rhombic, quadratic, etc.
  • Zooecial Wall: Skeletal wall of zooid. May be described as thin, thick, ring-like, etc.

Maculae: small patches (A distinct patch on the colony surface ) of more abundant mesopores. Maculae are the nonzooidal centres of monticules (

Monticule: Cluster of polymorphs which makes a prominence (“hummock”) on colony surface. (≈ Maculae). May be described as rounded, conical, knob-like, evenly spaced, conspicuous, inconspicuous, low, elongate.

Acanthostyle or Acanthopore: A type of stylet, style, spine or spike that protrudes from zooarial surface.

Cystiphragm: Curved partition that divides the zooecia transversely.

Diaphragm: Flat partitions that divide zooecia transversely (Across entire zooidal chamber).