Description:
Cerithidea scalariformis is a small, intertidal snail common in the Indian River Lagoon.  It reaches a shell length of 1 1/4 inches (3.2 cm).  The shell is light tan with reddish brown whorls having distinct sutures and a dark brown band running through the center of each whorl.  Ribs of the shell are gray, and the lip of the aperture is flared. 

Habitats: 
Ladder horn snails lead an amphibious existence in muddy habitats of tropical and subtropical estuaries. They are most numerous in October and November along tidal creeks in mangrove and salt marsh habitats.  Highest densities are found in the Salicornia zone.  C. scalariformis is highly eurythermal, and is also able to tolerate periods of desiccation. 

Similar Species: 
Two related snails resemble C. scalariformis.  The costate horn snail, C. costata, is an elongate, slender snail with a brown shell having whitish ribs.  It is somewhat smaller than C. scalariformis, its shell reaching only 5/8 inch (1.6 cm).  It is further distinguished by its ribs, which end at the body whorl, and by its aperture, which has a sharp edge rather than a flared one.  The plicate horn snail, C. plicata, is also very similar in appearance, but has distinctive yellow coloration in its ribs. 

Range:
Cerithidea scalariformis occurs in Georgia, both coasts of Florida, and in Cuba.  It is likely to occur throughout mangrove and salt marsh habitats in the Indian River Lagoon.