As a member of
few if any segments
are longer than wide, the notosetae
from the two sides do not almost meet along the dorsal
midline, the prostomium
does not extend as a dorsal
the segments posterior to it, there is no circle of tentacles around
has two antennae
and a pair of palps
are differentiated into two units, the distal unit of which is
even though it is smaller than the proximal unit (photo).
Some of the setae
into two parts, with a pair of stout jaws on the distal part and
on both parts (photo).
has four pairs of tentacular
cirri which arise on the anterolateral corners (photo).
Usually two pairs of eyes are present. The parapodia
on the first two setigers
on all subsequent
Both the notopodia
and the neuropodia
which are often small, plus one to three conspicuous lobes above and
The shape and arrangement of the ligules
varies among species. In Nereis
vexillosa the ventral cirrus of all parapodia
is simple, the tentacular
cirri of the peristomium
are not constricted into several units (photo),
segment behind the peristomium
is not expanded into a large collar around the peristomium
all of the paragnaths
on the eversible
are conical (not elongated transversely or comblike)(photo),
present on the distal part of the proboscis
and the upper
of the notopodia
in the posterior region is much larger than the lower ligule
and is strap-shaped, with a terminal cirrus (photo,
easily recognized characteristic). Color is greenish or
brown, often with blue tones; may appear iridescent in direct
Has 4 black eyes. The tentacular
cirri are short (photo).
The animal is often
large for a polychaete--up to 30 cm long and 1.2 cm wide.
vexillosa Grube, 1851
Common name(s): Banner sea-nymph, pile worm, sand worm, mussel worm,
vexillosa, about 24
cm long, found at Padilla Bay.
|(Photo by: Dave
Cowles, July 2009 )
How to Distinguish
from Similar Species:
The large, strap-shaped upper ligule
in the posterior notopodia
is very helpful in identifying this species. In Nereis
grubei and N.
the upper ligule
is not strap-shaped. Nereis
has no paragnaths
on the distal proboscis. Nereis
brandti has no homogomph
on the posterior
and the dorsal
is large and leaflike.
Alaska to San Diego;
Pacific coast of Russia
Mid to low intertidal
Intertidal with mussels
barnacles, on pilings, in sandy mud and cobbles, and in algal
The large jaws on the distal portion (maxillary ring) of the eversible
are used for
seizing prey or tearing algae (Nereids usually eat algae).
on the proximal portion (oral ring) are used for burrowing.
Family Nereididae are called sea nymphs and are common polychaete
worms in this area. Intertidal species are sometimes called
reproduce by releasing parts
of their body as epitokes,
which swim to the surface in mating swarms. Nereid
with eggs or sperm, large parapodia,
and large eyes. Day length is important in swarming of epitokes,
and near-shore lights can affect the timing of swarms. In our
spawning may occur shortly before midnight. The mating swarms
pheromones into the water which induces mating activity. The
and the females will not release their eggs unless in the presence of
males. The eggs are released into the water in the swarms,
ruptures in the body walls. In N.
vexillosa the female releases an agglutinating material
her eggs. Both male and female epitokes
(heteronereids) die after spawning. The mass, with eggs
to the bottom and grows to about the size of a bluish-green chicken
Larvae remain as plankton for hours to months. In the Pacific
the mating swarms usually occur in late winter or spring.
This worm is often used for fishing bait. It squirms
violently and everts
jaws when captured, and may bite.
and Fairbanks, 1966
and Snook, 1955
and Hanby, 2005
O'Clair and O'Clair
et al., 1985
General Notes and
abundances, unusual behaviors:
(right) has two antennae
and two large, two-segmented palps.
(segment behind the prostomium)
has 4 pairs of tentacular
cirri. This photo is a 3d composite made from a
series of photos
using a Keyence digital microscope. Photo by Dave Cowles,
of the partially distended pharynx
shows the large grasping jaws on the anterior portion and the sets of
conical teeth (paragnaths)
on several of the sections. The pharynx
is being distended because of pressure from my finger, which is visible
on the extreme left. Photo by Dave Cowles, June 2020
of the prostomium
of the same individual with the distended pharynx
above shows the undistended configuration. The prostomium
extends anterior to the peristomium
(to the right in this view) dorsally to the larger peristomium
(to the left in this view). The pharynx
is not visible because it is within the slitlike mouth on the peristomium.
Photo by Dave Cowles, June 2020
of the same individual shows a partly distended pharynx
from above. The pharynx
is not quite distended enough in this view to see the large anterior
jaws. but some of the paragnaths
are visible. Photo by Dave Cowles, June 2020
This individual kept gradually releasing eggs while being examined.
Many female polychaete worms store their eggs in their coelom (body
and release them through ruptures in the body wall. Where the eggs were
being released from this individual was not obvious--no large ruptures
were apparent. Nereids
eggs from a modified body or part of the body called an epitoke
so this individual is either already an epitoke
or is nearly ready to be modified into one. No agglutinating material
to be sticking these eggs together either, so the release of eggs was
as normally done in this species. Photo by Dave Cowles, June 2020
of the posterior body shows the prominent, straplike
with attached terminal
which are characteristic
of this species.
of the parapodia
shows the small aciculae
with large ventral
even larger dorsal
Most of the setae
compound (composed of more than one segment).
Closer examination by compound microscope would show this to be a homogomph
is a seta
in which the tip is comparatively blunt and curved. A homogomph
is a compound seta
in which the basal segment ends in a slightly expanded capsule, the two
sides of which are of approximately equal height (as opposed to heterogomph,
in which one side of the capsule is extended well out past the other).
Authors and Editors of Page:
Dave Cowles (2009): Created original page
CSS coding for page developed by Jonathan Cowles (2007)