Coney Island Local shells on Key
Atlantic Slipper Shell
Mud Basket Snail
Atlantic Oyster Drill
Shark Eye Snail
False Angel Wing
Hard Shell Clam
Soft Shell Clam
Use this dichotomous key to identify the common name of the shells found in the Coney Island. Choose one shell at a time to identify and start at the beginning of the key. Compare your observations of the shell to the questions below. Each set of questions will lead to another question about its characteristics until you arrive at a common name. Verify your hypothesis with the pictures below.
1. Is the shell part of a pair (bivalve) or a single shell ( univalve)? It belongs to a pair, Go to 11. Is a single shell, or univalve. Go to 2.
2. Does the shell have a spiral shape and an opening on it? Yes, Go to 4. No, Go to 3.
3. Is the shape rounded like an upside-down slipper? Yes, Atlantic slipper shell. No, go to 4.
4. Is the spiral shape pointed? Yes, go to 5. No, the spiral lies flat, go to 8.
5. Is the shell less than 1 inch (2.5 cm.) long? Yes, go to 6. No, it is larger than 1 inch, go to 7.
6. Does the spiral shape seem worn or have holes in it? Yes, Mud Basket Snail No, Atlantic Oyster Drill.
7. Does the spiral have points or bumps along the spiral? Yes, Knobbed whelk No, there is a deep groove around the spiral. Channeled whelk.
8. Does the spiral area lie flat against the shell? Yes, go to 9. No, it is pointed go to 4.
9. Is the shell one inch or less in size? Yes, Periwinkle snail. No, go to 10.
10. Is there a deep hole on the opposite side of the spiral, next to the opening? Yes, Moon snail, No, Shark Eye.
11. Does the shell belong to a matching pair? Yes, go to 12. No, go to 2.
12. Does the outside of the shell have bumps? Yes, go to 13. No, the surface is covered with ridges or lines that have a pattern. Go to 14.
13. Do the bumps have an irregular or random pattern or imprints of other shells? Yes, Virginia Oyster. No, go to 14.
14. Is the shell a circle in shape, have ridges that are 2mm or greater and form a star burst pattern? Yes, Bay Scallop. No, go to 15.
15.. Does the shape of the shell remind you of an angel wing? Yes, False Angel Wing. No, go to 16.
16. Is the shell brown and silvery with ridges (1mm apart) that extend across the long way of the shell? Yes, Ribbed Mussel No, go to 17.
17. Is the shell shaped like a long rectangle? Yes, Jack knife Clam. No, go to 18.
18. Is the shell white, opaque ( light cannot pass through it), thin and brittle? Yes, Soft Shell Clam No, go to 19.
19. Is the shell translucent (light passes through) pink to silvery grey, thin and brittle? Yes, Jingle Shell. No, go to 20.
20 . Is the shell smooth, dark in color with blue on the inside, thin & brittle? Yes, Blue Mussel. No, go to 21.
21. Is the shell thick, whitish, grey, with tiny ridges inside along the edge, may have purple areas on the inside? Yes, Hard Shell clam. No, go to 22.
22. Is the shell thick, white with grey/ blue age rings, triangle shaped, with a wide, even base? Yes, Surf Clam. No, go to 1.