  The ANTARES neutrino telescope, to be immersed depth in the Mediterranean
Sea, will consist of a 3 dimensional matrix of 900 large area photomultiplier
tubes housed in pressure resistant glass spheres. The selection of the optimal
photomultiplier was a critical step for the project and required an intensive
phase of tests and developments carried out in close collaboration with the
main manufacturers worldwide. This paper provides an overview of the tests
performed by the collaboration and describes in detail the features of the PMT
chosen for ANTARES.
