(from Coe, W. R. (1905). Nemerteans of the west and northwest coasts of America. Bull. Mus. comp. Zool. Harv.. 1-318)

Body usually comparatively short, broad and much flattened, not very contractile, and never coiled or much twisted. Mouth and proboscis opening slightly separated. Proboscis sheath possesses metamerically arranged lateral diverticula, commonly spreading out between the intestinal lobes as thin-walled sacs and connected with the rhynchocoel by comparatively narrow openings. Proboscis armed with numerous, commonly 20 or more, very small stylets situated on a large, sickle-shaped basis, and with numerous pouches of reserve stylets.

Cerebral sense organs very large, situated beside or immediately behind the brain. Ocelli numerous and of very large size. Lateral nerves situated ventrally, beneath intestinal diverticula. Brain and cephalic nerves very highly developed. Neurochord cells present.

These worms are seldom more than 5 to 10 cm in length, although a few forms are among the largest of the Hoplonemerteans. All are capable of swimming. But a single species of this genus is represented among the collections at hand.