In this paper, we show that the projective plane crossing number of th
e graphs C-3 X C-n is n - 1 for n greater than or equal to 5 and 2 for
n = 4. As far as we can tell from the literature, this is the first i
nfinite family of graphs whose crossing number is known on a single su
rface other than the plane. (C) 1993 John Wiley and Sons, Inc.