Snail id?

[cathbad]

I think I have narrowed it down to cerith but I'm not certain. Anyone have any ideas? Here are some pictures.

 

[cathbad]

And the other.

 

[cathbad]

That cerith is from the Sea of Cortez west on Mexico. These are from the east, from the gulf.

 

[cathbad]

These were hitchhikers. I thought they might be white ceriths but after looking at Kip4130's post on snails I'm not sure; they don't exactly resemble his photo example of a white cerith. Then I thought perhaps a trumpet snail but again the shells do not match the photos I found. Sprung has a photo of several different cerith shells from Florida is his invertebrate book which provides the closest match but still not exact.