Berkeley BioKeys: Invertebrates Home >> Invertebrates

Common Invertebrate Groups

Arachnids   class Arachnida
No wings, 8 legs. Includes spiders, mites, ticks, scorpions.

Insects  class Insecta
Biggest group. 6 legs. Head, thorax, abdomen. Includes flies, bees, ants, butterflies, beetles, etc.


Molluscs   phylum Mollusca
Soft bodies, often with a hard outer shell. Includes snails, slugs, clams, oysters, octopus.

Segmented Worms  phylum Annelida
Segmented worms. Includes earthworms and leeches.


Centipedes & Millipedes  class Myriapoda
Long body with many segments and many legs. Includes centipedes and millipedes.

Crustaceans  class Crustacea
Hard shell cover, two pairs of antennae. Includes crabs, shrimp, lobsters, barnacles.

More Resources