Spin superparticles and extended supersymmetry

A superfluid formulation of actions is suggested which describe the dynamics of relativistic massless particles possessing double superinvariance: the proper-time local n=1, 2 supersymmetry and global space-time N=1 supersymmetry. The dynamics of a free massless spin (n=1, N=1) superparticle is equivalent to the dynamics of a common superparticle with N=2 extended space-time supersymmetry. The spectrum of the quantum states of a spin (n=2, N=1) superparticle is found. It produces masslss N=1 supermultiplets with the spin content (1/2, 1), (1, 3/2)