Is there an 8mm Cassette Adapter?

There is no such thing as an "adapter" for 8mm to VHS. The adapter is only for VHS-C to VHS. The 8mm format, developed by Sony, is a "rival" of the VHS format developed by JVC. VHS tape is 1/2" wide, and 8mm is 1/3" wide. Actually, that is how 8mm gets its name: it is 8mm-wide tape (about 1/3 of an inch). And, finally, VHS uses what is called an "iron oxide" magnetic coating, while 8mm has a "metal" magnetic coating. All of these factors contribute to the total incompatibility of the 8mm and VHS formats. If you want to simply use an adapter to play back your Camcorder videos, you should select the VHS-C format as an alternative.