Trans-Tasman faunal migration is not, on present evidence, determinable for the early and mid-Tertiary faunas, but in the late Tertiary and Recent it has been from west to east—that is, from Australia to New Zealand.

A small archaic element common to the Recent faunas of Australia and New Zealand stems from a common mid-Tertiary fauna, and does not indicate later trans-Tasman movement.

Certain genera of New Zealand, or Australasian, origin have supplied contributions to the South American fauna, probably by means of the west to east circumpolar and west wind drifts. There is so far no evidence of South American elements in the Tertiary echinoderm faunas of Australasia.

The Recent echinoderm faunas of the Auckland, Campbell, Snares and Antipodes Islands, in the sub-Antarctic, have drawn their component genera and species from the New Zealand mainland fauna. These islands have a relatively shallow-water connection with New Zealand. The Recent echinoderm fauna of the nearby Macquarie Island, which stands in deep water, has been derived from the Antarctic, with the exception of one New Zealand echinoid. The latter has a pelagic larva.

It is concluded that shallow-water routes are of more importance in the dispersal of echinoderms than are relatively narrow deep-water gaps, unless the latter are traversed by a favourable ocean current. Trans-Tasman migration has probably made use of both former shallow-water routes and of planktonic dispersal of larvae in the East Australian current.