1a |
Edges of the siphonal
canal touching or nearly touching for at least part of the canal, so
this is essentially a closed tube |
2 |
1b |
Edges of the siphonal
canal not touching or nearly touching, so the canal is an open trough
for its entire length |
7 |
2a |
With a large tooth
on the outer lip of the aperture;
with 3 winglike axial excrescences, as well as unevenly spaced spiral
ridges; height up to about 8 cm (common intertidal and shallow subtidal
species)
|
Ceratostoma foliatum
(Gmelin, 1791) |
2b |
|
|
3a |
|
|
3b |
|
|
4a |
|
|
4b |
|
|
5a |
|
|
5b |
|
|
6a |
|
|
6b |
|
|
7a |
Height decidedly more then twice the diameter |
Trophonopsis lasius |
7b |
Height not more then twice the diameter |
8 |
8a |
Axial
ribs stout, not at all like lamellae |
9 |
8b |
Axial
ribs rather thin lamellae,
sometimes frilly |
12 |
9a |
Height much less then twice the diameter; outer lip of aperture,
in mature or nearly mature specimens, thickened to the extent that it is
more than half the width of the aperture
(height up to about 3 cm; locally introduced with the Pacific oyster, Crassostrea
gigas) |
Ceratostoma inornatum |
9b |
Heght about twice the diameter; outer lip of aperture
not thickened to the extent that it is half the width of the aperture |
10 |
10a |
Interior of aperture
purplish or brownish; spiral ridges more obvious between the axial
ribs than where they intersect the ribs; on oysters and barnacles in
areas where the Atlantic oyster, Crassostrea virginica, has been
introduced |
Urosalpinx cinerea |
10b |
Interior of aperture
usually light, not purplish or brownish; spiral
ridges generally as prominent where they intersect the axial
ribs as between the ribs; on rocky shores |
11 |
11a |
Axial
ribs broad, nearly contiguous, rounded, not sharply elevated; height
up to about 2.5 cm (common inertidal species) (Ocenebra lurida in
original key) |
Paciocinebrina lurida |
11b |
|
|
12a |
|
|
12b |
|
|
13a |
|
|
13b |
|
|