scyphozoan: any of various usually free-swimming marine coelenterates having a gelatinous medusoid stage as the dominant phase of its life cycle
coelenterate: radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures; they occur in polyp and medusa forms
inclusion body myositis: myositis characterized by weakness of limb muscles (especially the thighs and wrists and fingers); sometimes involves swallowing muscles; onset after 50 and slowly progressive; seen more often in men than in women