[yvonne]

http://www.ncaquariums.com/ask-the-aquar...-tortoises

Terrapins, often called diamondbacks because of the angular rings on their shells, are the only turtles in the world that live exclusively in brackish water. They have a light colored neck with small dark markings, a yellow plastron (lower shell) and webbed feet like freshwater turtles. Female terrapins are much larger than males, more so than any other North American turtle.

[yvonne]

http://www.ncaquariums.com/ask-the-aquar...-tortoises

Terrapins, often called diamondbacks because of the angular rings on their shells, are the only turtles in the world that live exclusively in brackish water. They have a light colored neck with small dark markings, a yellow plastron (lower shell) and webbed feet like freshwater turtles. Female terrapins are much larger than males, more so than any other North American turtle.