  Shell structure in the single particle spectrum of deformed harmonic
oscillator potentials when a term proportional to $(\vec L)^2$ is added is
analyzed for a large particle number. A scaling law which gives a dividing line
between regular and chaotic behavior in terms of energy, deformation and
strength of the $(\vec L)^2$ term has been found. According to this law, shell
structure survives for higher particle numbers only with lesser deformation.
