Phlebobranchia is a suborder of sea squirts in the order Enterogona. The group includes both colonial and solitary animals. They are distinguished from other sea squirts by the presence of longitudinal vessels in the pharyngeal basket. This provides the etymology of their name: in ancient greek, φλέψς, φλεβός means "blood vessel". An other characteristics of phlebobranchians are the gonads being surrounded by a loop of gut. The posterior part of the abdomen is absent, and many species also lack the epicardial cavity that surrounds the heart and other internal organs in many other sea squirts.