Bryozoans

Bryozoans

Bryozoans are colonial animals of uncertain evolutionary descent. They may be related to freshwater rotifers. Bryozoans are found in the lower intertidal to subtidal zones, attached to a firm substrate, and also in brackish water. Individual animals are too small to see with the naked eye.

Bryozoan growth forms range from encrusting, forming coatings on hard surfaces, to bushy. An entire colony may bear a superficial resemblance to a hydroid colony, although bryozoans are internally more advanced than cnidarians. Bryozoan colonies grow to 3", and are occasionally larger.

Bryozoan anatomy
Note separate mouth and anus, unlike hydroid
Spiral Tufted Byozoans
Spiral Tufted Byozoans Amanthia spp

Portuguese Man-O-War

Siphonophores are free-floating or swimming colonial hydroids. All siphonophores are predatory and should be treated with respect for their venomous sting. Some of the individual animals along the length of the colony provide tentacles for defense (dactylozooids) and food capture, while others may function as swimming bells (nectophores), aid flotation (pneumatophore), provide additional defense (bracts), digest prey (gastrozooids), or serve for reproductive functions (gonozooids.) Whether siphonophores are single individuals or colonies of well-integrated polymorphic hydroid and medusoid individuals is a matter of debate among specialists.

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