Setting address ranges for allowed cups printing?

[unruh at physics.ubc.ca]

I have about 40 machines (from x.x.x.10 to x.x.x.50 IP addresses) that I want to allow to print to my printer. How can I specify a range without listing each of the machine addresses individually?
As one possibility, I tried
x.x.x.0/26 ( which would I though allow through addresses 0 to 63) which seems to work, but of course also allows through more than I want.