Semaphore Signal Issue 1 has the following to say about them:
Among the various innovations introduced by Apple in its Lisa product is yet another style of floppy disk. You won't yet find this particular disk on the shelves of many computer stores. The only name we've found for it so far is 687-8001 (the packing list entry for a box of five blank disks). The manuals don't say, but a source from Apple assures us that the edge notch not on the corner is the one for write protecting the disk.
You can find out more about Twiggy media (aka FileWare) here http://www.brouhaha.com/~eric/retrocomputing/lisa/twiggy.html[LisaFAQ] > [Hardware] > [Floppy, Twiggy, and Tape media used with the Lisa] (Comment on this answer)