Help tell the difference in land or marine hermit!?

My friend came back from the beach last weekend and brought me some seashells. I left them on my desk and went to bed, the next morning one was in the floor. Come to find out there was a tiny little hermit inside. We don't live near the beach and I would hate for this little guy to suffer a horrible death because I do not know how to care for him. If there are things I can check to know if he is a land or marine hermit, it would help a ton. Right now I have him in sand in a moist crabitat. It's been about four days now and with daily misting he is starting to come out, only when i put him on my hand but not in the cage. He hasn't eaten anything and has not been near the water, both fresh and salt. I'm afraid if he doesn't at least eat something soon he won't last much longer. My friend said he found him further up the beach not really near the water. I do not know if that will help any.