The mermaid's glove has decorative branches which often fuse together, resembling antlers. In Dutch, it is called 'antler sponge'. If the waters are calm where it grows, the branches are thin, resembling fine fingers. Probably the reason it's called mermaid's glove in English. In wilder waters, the branches are wider and flatter. This sponge gets its food by sucking up water through tiny pores. Other pores visible on the branches are used for expelling the filtered seawater.