Umbraculoidea

Umbraculoidea
This is a group with a very small number of species. There are only two families represented in this order with a very small number of species within each family.

The main characteristics are possession of an external, flattened or raised limpet-like shell on the dorsum and a gill located on the right side under the shell between the mantle and the foot. The rhinophores are hollow and rolled like a cylinder of paper. They feed upon sponges.