Nereis, the sandworm

Class Polychaeta

• parapodia
• prostomial palp
• prostomium
• prostomial tentacle
• peristomial tentacles
• eye
  
  

Class Polychaeta

Hermodice, the fire worm

Class Polychaeta

Aphrodite, the sea mouse

Class Polychaeta

fan worms

• forewing
• pronotum
• mesothorax
• metathorax
  

• tympanum
• spiracle

• Trochanter of leg III
• Coxa of leg III
• prosternum
• mesosternum
• metasternum
• Abdominal sternite

• antenna
• ocellus
• labrum
• Compound eye
  

• male

• epiproct
• paraproct
• Female ovipositor
  

• labrum
• mandible
• maxilla
• labium
• hypopharynx

• tibia
• tarsus
• trochanter
• coxa
• femur

Phylum Arthropoda. 

I.Trilobites, Chelicerates, and Crustacea