Their burrow is U-shaped , with the animal 's tentacles projecting from one end .
Like their relatives , they are adapted for burrowing into soft sediment , but they are relatively sedentary , rarely moving once they have excavated their burrow .
relatives burrow burrow is U-shaped , with the animal 's tentacles projecting from one end .
Like their relatives , they are adapted for burrowing into soft sediment , but they are relatively sedentary , rarely moving once they have excavated their burrow .