The Ear Snails 



M. bidentatus, Say, is the commonest salt marsh snail 

 on the Atlantic and Gulf coasts. It climbs the marsh grasses 

 at high tide as if to escape a ducking. The white cross folds deep 

 in the outer lip and two tooth-like folds on the columella are 

 characteristic of them all. The shells are thin and horn-coloured, 

 broadly ovate, square shouldered, polished and often banded 

 when young. Adult shells are corroded and coated with muddy 

 deposits. Length, ^ inch. 



Habitat. — New England to Texas in salt marshes. 



M. olivaceus, Cpr., is a plump oval shell, smooth, dirty 

 white banded or splotched with purple, under an olive green 

 epidermis. The aperture is white, with sharp cross folds within 

 the outer lip, and a single central lamina prominent on the col- 

 umella. Length, h inch. 



Habitat. — San Diego, Gal. 



289 



