| 1a |
Spiral
ridges and grooves limited to the lower portion of the body
whorl |
2 |
| 1b |
Spiral
ridges and grooves not limited to the lower portion of the body
whorl |
5 |
| 2a |
Uppor portion of body
whorl with a well developed ridge (this is often of a lighter color
than the rest of the shell); outer lip of aperture
with a prominent indentation below the point where the ridge meets the
lip; color generally yellow-brown to brown, sometimes with white or dark
brown mottling (height to about 1 cm) |
Alia carinata |
| 2b |
Upper portion of body
whorl without a well developed ridge (in A. gausapata, there may be
a slight ridge); outer lip of aperture
without a prominent indentation (if there is a slight ridge on the body
whorl, there may be an outwardy directed projection where the ridge
meets the lip); color usually brown or tan |
3 |
| 3a |
Outer lip of aperture
evenly curved (periostracum
brown; length to 1.5 cm, subtidal) |
Alia permodesta |
| 3b |
Outer lip of aperture
not evenly curved (a portion of it is nearly straight) |
4 |
| 4a |
Siphonal
region, when the shell is viewed with the aperture
facing away from the observer, not obviously set off from the rest of the
body
whorl; height
to 1.1 cm; intertidal and subtidal (Alia gausapata in original key) |
Astyris gausapata |
| 4b |
Siphonal
region, when the shell is viewed with the aperture
facing away from the observer, obviously set off from the rest of the body
whorl; height
rarely more than 9 mm; subtidal |
Alia tuberosa |
| 5a |
Axial
ridges obviously not parallel to the long axis of the shell (they are
directed slightly to the left as they extend downward); height
rarely attaining 1.5 cm (often with distinctive light and dark markings
unless the shell is covered with foreign material) |
Amphissa versicolor |
| 5b |
Most axial
ridges almost parallel to the long axis of the shell |
6 |
| 6a |
Middle third of the outer lip of the aperture
(in mature specimens, at least 2 cm high)
parallel to the long axis of the shell (photo);
height
to 3 cm; common intertidal and subtidal species |
Amphissa columbiana |
| 6b |
Middle third of the outer lip of the aperture
(in mature specimens, at least 1 cm high)
curved; height
to 1.5 cm; subtidal, rare |
Amphissa reticulata |