title: Polyzoniida
text: # Polyzoniida
  
  Polyzoniida is an order of millipedes in the subterclass Colobognatha containing three families and at least 74 described species.
  
  ## Description
  
  Polyzoniidans have a somewhat domed dorsal surface with a flat ventral side. Their heads are small and cone-like, with few ocelli. They lack a dorsal groove and paranota (lateral extensions of each segment).
  
  ## Classification
  
  The order Polyzoniida contains three families:
  
      Hirudisomatidae Silvestri, 1896 (6 genera, 20 species)
      Polyzoniidae Newport, 1844 (6 genera, 22 species)
      Siphonotidae Cook, 1895 (15 genera, 40 species)
  
  ## Distribution
  
  The family Hirudisomatidae occurs from Spain to the Himalayas in Eurasia, Japan, and in North America from southwest Canada to central Mexico. Polyzoniidae has a holarctic (northern hemisphere) distribution, occurring in the northwest and northeast United States, eastern Canada, and in Europe from the United Kingdom and France to Siberia. Siphonotidae has a southern distribution, occurring in Brazil and Chile, South Africa, Southeast Asia, Indonesia, Tasmania, and New Zealand.
  
  