Forbes and Goodsir, 1841
Description
External appearance
Solitary. Body elongated and bottle-shaped, up to 140 mm in length. Test wrinkled, coated with sand and mud, bearing fibrils towards the base.
Characters
Both siphons small, 4-lobed and placed close together anteriorly. From 20-30 simple branchial tentacles of variable size. Branchial sac with numerous rows of straight stigmata; no folds; with 20-30 longitudinal bars on each side. Gut left of branchial sac; stomach distinct, rounded, with 20 narrow longitudinal folds and a single small liver diverticulum. One U-shaped gonad on each side, consisting of an ovary and a series of small male follicles on the sides (P. corrugata morphology).
Habitat
Unattached and partly imbedded in sand or mud; from shallow water down to depths of 200 meters.
Distribution
Artic-Boreal distribution.