Polymastia pacifica, the aggregated vase sponge, is is a demosponge (family Polymastiidae), sometimes called the aggregated nipple sponge because it has a pale white/yellow color, the base often covered in sediment, and projections making it look like a cow udder. This sponge is found on sandy rock surfaces in the low intertidal to depths of at least 25 meters (80 feet) along the Pacific coast of North America from Alaska to southern California.Individual sponges grow to 2 cm in height and may aggregate in colonies 60-90 cm (2-3 feet) across.End tips of the individual sponges are often nibbled by fish or other predators (Washington State University Vancouver, 2014; Bisby et al. 2005; Bushing 2008).
