Bonus Opportunity !!!

This interesting creature floated up on the beach when we were in Monterey California this summer. There were literally hundreds of them on the beach. There are tentacles on the bottom of this critter but I'm not sure they sting. For 5 bonus points find out either the common name or scientifc name of this species and email your answer to me. Hint: It is not a jellyfish. It is considered a hydroid.