Cnidarian (Coelenterates) Vocab

Epidermis

Outer layer of cells of a body wall

Gastrodermis

The inner layer of cells lining the gastrovascular cavity

Mesoglea

A gel-like matrix between the epidermis and gastrodermis

Cnidocytes

Stinging cells on tentacles that produce cnida

Cnida

Organelle characteristic of cnidarea used for defense, food gathering and attachment

Polyp

Hydroid, sessile stage in the life cycle

Medusa

Jellyfish, free swimming stage in the life cycle

Nematocyst

Stinging cells with venom

Gastrovascular cavity

Large central cavity that digests food with a single opening as the mouth and anus

Hydrostatic skeleton

Skeleton supported by body cavity fluids that are confined by the body wall

Planula

Ciliated, free-swimming larva that develops following reproduction and metamorphoses into a polyp

Statocyst

Gravity sensing cells

Pedal disk

The surface opposite to the mouth of a sea anemone

Protandry

The condition in monoecious organisms that male gonads mature before female gonads to prevent self-fertilization