Scyphozoa is further divided into 4 different orders. There are sessile-cup shaped forms, which lack a free swimming medusa form. The Order Coronatae are rarely witnessed as they include deep sea living jellyfish. The Order Semaeostomae are the disc jellyfish which include the largest jellyfish of all, the Arctic Lion's Mane jelly. These jellyfish are extremely large and contact with one of these could kill a human. The largest ever had a "bell" 7 feet long and tentacles that reached over 120 feet long. The last of the 4 orders is Rhizostomae. This order includes the jellyfish that lack tentacles and have 8 oral arms instead of four. Instead of one large mouth in the middle of this body, (called the manubrium), it has grown multiple mouth openings at the end of its oral arms, where it can reach out and digest animals by use of those oral arms, instead of using their tentacles. Often, the whole body surface of the animal is covered in nemocysts to sting the prey, not just the tentacles.