Trochospongilla horrida, een nieuwe spons voor Nederland (Porifera: Spongillidae)

Trochospongilla horrida, a new sponge species for The Netherlands (Porifera: Spongillidae) Trochospongilla horrida is recorded in the Netherlands for the first time. It was recently discovered during a survey of invertebrates of the river IJssel. A description of the sponge material is given and records of other sponges occurring along with it in the river IJssel are provided. The specimens are kept in the collections of the Zoölogisch Museum Amsterdam.