Stomolophus meleagris, the cannonball jellyfish (family Stomolophidae), is a rhizostome scyphozoan abundant in coastal waters of the Atlantic and Gulf of Mexico coasts of North America, recognized by its compact, dome-shaped bell with a distinctive brown pigmented border and greatly reduced, fused oral arms lacking long tentacles. It is harvested commercially in significant quantities for export to Asian markets as a processed food product. Its blooms are seasonally predictable and create both ecological impacts and commercial harvesting opportunities. Genomic data have been generated for this species and are available in public databases, enabling comparative studies of cnidarian evolution and ecology.