Diamond has posted the April Previews Order Form on its Website and retailers have noticed that there are no Marvel comics listed at $2.25, though numerous popular series such as Amazing Spider-Man, Wolverine, Ultimate Spider-Man, Ultimate Fantastic Four, Ultimate X-Men, X-Men, Uncanny X-Men and Marvel Team-Up, which have previously been selling for $2.25, are now listed at $2.50.  ICv2 has attempted to contact Marvel about the price increases, but Marvel has not replied to our inquiries.  If, as appears likely, this is a permanent price change, it will mark Marvel's first price increase since April of 2003, when the nation's number one comic book publisher raised prices on its lowest-selling series.  In contrast to that change, this price increase affects many of Marvel's best-selling titles.