Hippoporina pertusa is an encrusting bryozoan that develop broad spreading sheets which are reddish to orange. Autozooids are broad, rectangular or polygonal, flat or slightly convex. They are 0.6-0.7 by 0.35-0.5 mm and radiate from the centre.
Hippoporina pertusa is essentially a warm temperate species that is distributed in the eastern Atlantic from southern and western Britain to the Mediterranean and West Africa. In Britain, it ranges north to the Hebrides and is not uncommon on the shell banks in the western Channel. It is known from the Isle of Man, Cornwall, south Devon, Guernsey and the coast of Antrim. Elsewhere, it has been recorded from the Gulf of Mexico, California and the Galapagos Islands
The species is able to colonise hard substrates, especially large shells, in offshore waters.