Larger tubes house larger animals with more gametes than do smaller ones.
The two ends of each tube protrude from the bottom of sand flats. Specimens from southern latitudes are either benthic and can be collected by diving or are intertidal and can be collected with a shovel at very low tides. Specimens from Woods Hole are benthic and are collected by diving. The reproductive season is longer in Southern populations. This species is also very common in Florida, but we have not investigated these specimens.