| 1a |
Without a pronounced groove separating
most of the body whorl
from its lower portion (up to about 3 cm high; usually blackish brown;
common in some muddy bays to which it has been introduced from the
Atlantic
coast) |
Ilyanassa obsoleta |
| 1b |
With a pronounced groove separating most of the
body whorl from its
lower portion |
2 |
| 2a |
Axial ribs prominent, but spiral ridges evident
only on the body whorl
(there are about 3 or 4 of them just above the groove) (up to about 1.5
cm high; introduced into a few bays in the Puget Sound region) |
Nassarius
fraterculus |
| 2b |
Spiral ridges prominent on most whorls |
3 |
| 3a |
Inner lip of aperture with a broad, usually
orange callus that spreads
out over the body whorl, well above the termination of the outer lip;
axial
ribs (which may or may not be prominent) not reaching the groove near
the
base of the body whorl; height up to 4.5 cm |
Nassarius
fossatus |
| 3b |
Inner lip of the aperture without a large orange
callus (if the callus
spreads out over the body whorl, it does not go higher than the
termination
of the outer lip); axial ribs reaching the groove near the base of the
body whorl; height rarely exceeding 3 cm |
4 |
| 4a |
Axial ribs (of which there are more than 20)
about equal to the spiral
ridges, the two intersecting in such a way as to form nearly evenly
spaced
beads [the beads may not be visible without magnification] |
5 |
| 4b |
Axial ribs (of which there are about 12) much
more pronounced and more
widely spaced than the spiral ridges (the two do not intersect in such
a way that they form nearly evenly spaced beads) (Nassarius
mendicus
in original key) |
Hima mendica |
| 5a |
Axial ribs generally not prominent, but the beads
formed where they
intersect with the spiral ridges are obvious without magnification;
spiral
ridges on body whorl all about the same size (there is no regular
alternation
of large and small ridges); height to about 3 cm (not likely to be
found
north of Oregon) |
Nassarius rhinites |
| 5b |
Axial ribs and spiral ridges about equally
prominent, intersecting
to form a cancellate pattern, but beading is not evident without
magnification;
spiral ridges on body whorl not all of the same size (larger ribs
alternate
with smaller ones); height to about 2 cm |
Nassarius perpinguis |