Hidden about 30 centimeters beneath the soft soil of the littoral zone are rafts of these communal hunters. Often numbering in the scores, these dart-shaped creatures lie in wait for the unwary passerby to tread on the soil directly above them. As they rely primarily on their sensitive pressure receptors, their sonar is nearly nonexistent. These short-range attack hunters are able to propel themselves with enormous velocity over short distances. They launch themselves by means of a folded, muscular "foot" that snaps the individual animal through the concealing ground toward its target. After a kill, the beachquills will instinctively regroup and bury themselves, leaving no visual evidence of their existence. Their immobility and silence are perfectly evolved hunting techniques on a sonar-b