1. Jointed footed creatures
Arthropoda
Jointed footed creatures

2. Members of the Arthropoda
Peripatus--Onychophoran--velvet worm
Chelicerates
Mites
Pycnogonids
Arachnids
Horseshoe crabs (Limulus)
Mandibulates
Hexapoda
Crustacea
Myriapod (centipedes and millipedes)

3. Characteristics Segmental Every segment has a pair of appendages
Tagmatamization
Head thorax abdomen, prososoma, opisthosoma
Every segment has a pair of appendages
Monoramous or are they biramous (common basal segment with endopodite and exopodite as branches)
Exoskeleton-
Structure
Chitin-mucopolysaacharide
Ecdysis (moulting)

4. More characteristics Respiratory devices
Gills (ctenidial), book gills/lungs, series of tubes that end in very small tubes adjacent to all tissues in the body. Tracheal system, tracheoles
Haemocoel--cavity of the blood and the cavity of the body are contiguous
Open circulatory systems
Separate sexes
Fairly well developed nervous system, ladder-type nervous system.