Polyzoniida
# 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.

