experimental techniques, the dots will definitely be understood better and better, and they will serve as a rich source of information on many-body physics in the coming years.

In the theoretical aspects, detailed information on electronic structures has been obtained for the systems with a smaller N (say, N$<$10)$%
^{2,4,6}$.  When N is small, the effect of symmetry was found to be very important, e.g., the magic angular momenta of few-electron dots originate from the constraint of symmetry$^{11-13}$. When N is larger (say, N $\geq $10), the effect of symmetry is scarcely studied. The systems with a larger N are themselves very attractive, because they might possess both the features of few-body and many-body systems. Thus the understanding of these systems might serve as a bridge to connect few-body and many-body physics. In a previous paper, the electronic structures of a dot with nine electrons have been studied$^{13}$. The present paper is a continuation of the previous one, and is dedicated to the study of the dot with N=13 and with the spins polarized. The choice of thirteen is rather arbitrary, just because it is explicitly larger than the systems with N$<$10 which have already been extensively studied, and because 