Porpita porpita — the blue button jelly — is a neustonic species mostly found in the tropics; that is, it floats right near the surface of the water. The circular disc is made of chitin and filled with gas, allowing these jellies to float. The tentacles (zooids) radiating from the disc do all the feeding. This one was collected by a graduate student while diving in the waters around a remote island in Pacific Panama.
Visit Website | Image credit: Kelly Rakow, Woods Hole Oceanographic Institution