Cubozoa
Cubozoans are marvelous animals. They are amazing box jellies with complex eyes and potent toxins. They look like normal jellyfish, but they can swim extremely fast, glide around barriers, and have fairly good vision considering they do not have a brain. Cubozoans have a cube shape when seen from above, which is how they got their name. They have four evenly spaced out tentacles, or bunches of tentacles. Not surprisingly, given their squishy figure, there are not many fossil cubozoans known to date. Today, there are about 20 known species found in tropical and semitropical waters. They are umbrella shaped rather thandomed or crowned-shaped. The bottom of the umbrella includes a flap, concentrating and increasing the flow of water expelled from the umbrella. As a result, cubozoans move more rapidly than other jellyfish.