YES.
Scientists think that the first form or cnidarians was the larvae long ago. No the medusa or polyp if that is what you are thinking.
Check on wikipedia if you don't believe me
Medusa
Medusae
Polyp
polyp
a crazy guy named Steve
a crazy guy named Steve
a crazy guy named Steve
Medusa
No they do not.
The plural of the word larva is the Latin plural larvae.The English plural "larvas" is less commonly used.
larvae
An adult swimming cnidarian is called a medusa.