Height (mm): 25
Conical shell that is taller than it is wide. 8-10 shell whorls with many spiral grooves.
Massachusetts to Texas
0 to 22 meters
Marine; Shallow coastal salt marshes and intertidal zones
The Marsh Periwinkle can not survive on seagrass alone. One way they supplement their diet is by "farming" fungus. They do this by eating holes in cordgrass and spreading waste on the surface to create the ideal conditions for the fungus to grow.
MolluscaBase eds. (2021). MolluscaBase. Littoraria irrorata (Say, 1822). Accessed through: World Register of Marine Species at: http://marinespecies.org/aphia.php?p=taxdetails&id=419566 on 2021-06-10
Morris, P. A. (1987). A field guide to shells: Atlantic and Gulf coasts and the West Indies (3rd ed.). Houghton Mifflin.