This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. Plural form of jellyfish.

"There are of course a great number of animals -- such as jellyfishes, and other animals -- without any hard parts, of which we cannot reasonably expect to find any traces whatever: there is nothing of them to preserve."