  We present new dynamical models of the S0 galaxy N3115, making use of the
available published photometry and kinematics as well as of two-dimensional
TIGER spectrography. We first examined the kinematics in the central 40 arcsec
in the light of two integral f(E,J) models. Jeans equations were used to
constrain the mass to light ratio, and the central dark mass whose existence
was suggested by previous studies. The even part of the distribution function
was then retrieved via the Hunter & Qian formalism. We thus confirmed that the
velocity and dispersion profiles in the central region could be well fit with a
two-integral model, given the presence of a central dark mass of ~10^9 Msun.
However, no two integral model could fit the h_3 profile around a radius of 25
arcsec where the outer disc dominates the surface brightness distribution.
Three integral analytical models were therefore built using a Quadratic
Programming technique. These models showed that three integral components do
indeed provide a reasonable fit to the kinematics, including the higher
Gauss-Hermite moments. Again, models without a central dark mass failed to
reproduce the observed kinematics in the central arcseconds. This clearly
supports the presence of a nuclear black hole of at least 6.5 10^8 Msun in the
centre of NGC 3115. These models were finally used to estimate the importance
of the dark matter in the outer part of NGC 3115, suggested by the flat stellar
rotation curve observed by Capaccioli et al. (1993).
