Hmn, tricky. I know of plenty of Win32 file splitters, but I havent seen any Mac ones. I' say your best bet would be StuffIt Expander... of course, afaicr, the Mac version of it is 5meg or so, so getting it onto your Mac could be a problem, unless you've already got it... It's a pretty standard piece of software to have.
If you don't have it, check their website
for older versions. Or try the Macintosh Emulation Station
for anything that might help. They have *tons* of 68k software there.
"How appropriate. You fight like a cow."