Hymeniacidon

Hymeniacidon
Scientific classification
Kingdom:	Animalia
Phylum:	Porifera
Class:	Demospongiae
Subclass:	Ceractinomorpha
Order:	Halichondrida
Family:	Halichondriidae
Genus:	Hymeniacidon

Hymeniacidon is a genus of sponges in the class Demospongiae. Some members of the genus are known to be mobile, achieving speeds of between 1 and 4 mm per day.

Species so far described in this genus include:

...
Wikipedia