During Dive 05 of the Windows to the Deep 2019 expedition, we encountered a charismatic swimming jelly called a helmet jelly that was twisting and tumbling as it moved across remotely operated vehicle Deep Discoverer’s field of view. With a characteristic groove encircling its swimming bell, the helmet jelly is classified as a coronate scyphomedusa, with a scientific name of Periphylla periphylla.

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