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

Woodworth's diagnosis of this genus of pelagic nemerteans is as follows:

"A common external opening for the mouth and proboscis. Supraoesophageal ganglia smaller than suboesophageal. Median dorsal vessel present. Lateral diverticula of the intestine very numerous."

To this diagnosis the family characters of the Palagonemertidae of Moseley to which the genus belongs may be added:

"Pelagic nemerteans with broad, flattened, leaf-like, gelatinous, very hyaline body. Rhynchocoel extending nearly the entire length of the body. Proboscis unarmed. No cephalic grooves or organs of special sense. Intestinal tract dendrocoelous."