The Crustaceans (Crustacea) - subphylum
more then 67,000 species
The (Thylacocephala) - class -extinct-

(Concavicarida)
- order -extinct-

(Conchyliocarida)
- order -extinct-
The Shrimps (Branchiopoda) - class
(Sarsostraca) - subclass

(Anostraca)
- order
The Fairy Shrimps & Clam Shrimps (Phyllopoda) - subclass
The Water Fleas
(Cladocera)
- order

(Lipostraca)
- order -extinct-
The Tadpole Shrimps
(Notostraca)
- order
The Clam Shrimps (Diplostraca) - infraclass
The Clam Shrimps
(Laevicaudata)
- order
The Clam Shrimps
(Spinicaudata)
- order
The Clam Shrimps
(Cyclestherida)
- order
The Water Fleas
(Cladocera)
- order
Around 620 species
The Blind Crustaceans (Remipedia) - class

(Enantiopoda)
- order -extinct-

(Nectiopoda)
- order
Horseshoe Shrimps (Cephalocarida) - class
Horseshoe Shrimps
(Brachypoda)
- order
Barnacles & Copepods (Maxillopoda) - class
(Thecostraca) - subclass

(Laurida)
- order

(Dendrogastrida)
- order
The Barnacles (Cirripedia) - infraclass
Barnacles (Acrothoracica) - superorder

(Pygophora)
- order

(Apygophora)
- order

(Lithoglyptida)
- order

(Cryptophialida)
- order
(Rhizocephala) - superorder

(Kentrogonida)
- order

(Akentrogonida)
- order
(Thoracica) - superorder

(Pedunculata)
- order

(Sessilia)
- order
(Tantulocarida) - subclass

(Basipodellidae)
- family

(Deoterthridae)
- family

(Doryphallophoridae)
- family

(Microdajidae)
- family

(Onceroxenidae)
- family
The Fish Lice (Branchiura) - subclass

(Arguloida)
- order

(Cyclida)
- order -extinct-
The Tongue Worms (Pentastomida) - subclass

(Cephalobaenida)
- order

(Porocephalida)
- order

(Raillietiellida)
- order

(Reighardiida)
- order
(Mystacocarida) - subclass

(Mystacocaridida)
- order
(Copepoda) - subclass

(Calanoida)
- order

(Cyclopoida)
- order

(Gelyelloida)
- order

(Harpacticoida)
- order

(Misophrioida)
- order

(Monstrilloida)
- order

(Mormonilloida)
- order

(Platycopioida)
- order

(Poecilostomatoida)
- order

(Siphonostomatoida)
- order

(Sessilia)
- order
Seed Shrimp (Ostracoda) - class

(Myodocopida)
- order

(Halocyprida)
- order

(Platycopida)
- order

(Podocopida)
- order
Crabs, Crayfish, Lobsters (Malacostraca) - class
(Phyllocarida) - subclass

(Archaeostraca)
- order -extinct-

(Hoplostraca)
- order -extinct-

(Leptostraca)
- order
(Hoplocarida) - subclass

(Aeschronectida)
- order -extinct-

(Archaeostomatopoda)
- order -extinct-

(Stomatopoda)
- order
(Eumalacostraca) - subclass
(Syncarida) - superorder

(Palaeocaridacea)
- order -extinct-

(Bathynellacea)
- order

(Anaspidacea)
- order
(Peracarida) - superorder

(Spelaeogriphacea)
- order

(Thermosbaenacea)
- order

(Lophogastrida)
- order

(Mysida)
- order

(Mictacea)
- order

(Amphipoda)
- order

(Isopoda)
- order

(Tanaidacea)
- order

(Cumacea)
- order
(Eucarida) - superorder

(Euphausiacea)
- order

(Amphionidacea)
- order
Crabs, Lobsters & Shrimps
(Decapoda)
- order