Chiropsalmus quadrumanus
Chiropsalmus quadrumanus, commonly known as the four-handed box jellyfish, is a species of box jellyfish found in the western Atlantic Ocean, the Gulf of Mexico and the Pacific Ocean. The sting is venomous and dangerous to humans, especially children.
Carybdea
Carybdea is the only genus of venomous box jellyfish in the family Carybdeidae. "Carybdea sivickisi" is known as the smallest species in the genus and is sexually dimorphic.As of August 2013, the following genera previously classified in this family have been reassigned to the family Carukiidae: