Baseodiscus princeps (Coe, 1901)

Common name(s): 

Phylum Nemertea
Class Anopla
Order Heteronemertea
Family Baseodiscidae
Baseodiscus princeps from March Point, Padilla Bay, WA
(Photo by: Dave Cowles, July 2007)
Description: As with all members of Class Anopla, this nemertean worm has a mouth separate from the proboscis pore, both openings are on the ventral side of the head behind the brain, and the proboscis has no stylets.  Baseodiscus princeps has no cephalic slits on the head but it does have many eyespots (photo) and an inconspicuous pair of oblique grooves on the head's anteroventral surface.  Its color is a mostly homogeneous ochre to brownish dorsally and lighter yellow-ochre ventrally, with no longitudinal or annular lines.  The animal is highly contractile, and may be able to expand to longer than 1 m.

How to Distinguish from Similar Species:  Tubulanus polymorphus is also uniformly orange or reddish but it has no eyespots nor anteroventral grooves.  The description of this species sounds very much like that of B. punnetti from farther south.

Geographical Range:

Depth Range:


Biology/Natural History:  The animal is able to contract its body in such a way as to form annular regular folds along the body (photo).    It can contract its head entirely into its trunk.



Dichotomous Keys:
  Kozloff 1987, 1996

General References:

Scientific Articles:

Web sites:

General Notes and Observations:  Locations, abundances, unusual behaviors:

The head is lighter dorsally than is the rest of the dorsum, and has a line of dark eyespots around the border.

The underside is lighter than the dorsum, as seen in this view of an upraised head.

The animal can constrict its muscles to form annular constrictions.

Authors and Editors of Page:
Dave Cowles (2007):  Created original page
Jonathan Cowles (2007):  Updated page with CSS