Herdman, 1882
Description
External appearance
Solitary. Body elongate and club-shaped, narrow at the base, up to 120 mm in length. Test leathery, wrinkled and mammilated.
Characters
Both siphons 4-lobed and placed close together anteriorly. Branchial tentacles simple. Branchial sac with numerous rows of straight stigmata; four branchial folds on each side. Gut left of branchial sac; stomach with longitudinal folds and a single small liver diverticulum. Gonads on both sides (2-4 on the left, 4-8 on the right); consisting of a long and narrow ovary surrounded by male follicles (S. clava morphology).
Habitat
Attached to hard substrata; in shallow water.
Distribution
In the southern part of the North Sea; introduced from the Pacific area.