  A compartmentalized surface model of Nambu and Goto is studied on
triangulated spherical surfaces by using the canonical Monte Carlo simulation
technique. One-dimensional bending energy is defined on the skeletons and at
the junctions, and the mechanical strength of the surface is supplied by the
one-dimensional bending energy defined on the skeletons and junctions. The
compartment size is characterized by the total number L^\prime of bonds between
the two-neighboring junctions and is assumed to have values in the range from
L^\prime=2 to L^\prime=8 in the simulations, while that of the previously
reported model is characterized by L^\prime=1, where all vertices of the
triangulated surface are the junctions. Therefore, the model in this paper is
considered to be an extension of the previous model in the sense that the
previous model is obtained from the model in this paper in the limit of
L^\prime\to1 The model in this paper is identical to the Nambu-Goto surface
model without curvature energies in the limit of L^\prime\to \infty and hence
is expected to be ill-defined at sufficiently large L^\prime. One remarkable
result obtained in this paper is that the model has a well-defined smooth phase
even at relatively large L^\prime just as the previous model of L^\prime\to1.
It is also remarkable that the fluctuations of surface in the smooth phase are
crucially dependent on L^\prime; we can see no surface fluctuation when
L^\prime\leq2, while relatively large fluctuations are seen when L^\prime\geq3.
