When saltwater cravings overwhelm you, you may as well go all out. There are fish specialists everywhere, but 4 Bells refuses to be constrained. Behold: dozens of critters arranged on piles of crushed ice, next to yellow wedges of sour lemon and pots of cocktail sauce. These are sculptural towers of shellfish, designed to put your company's expense account to the test. (Yes, surprise your out-of-town business guests with fruits de mer as fresh as those from any coast.)There's whole fried snapper, the likes of which are generally only available at the finest Thai places, and then only if you scour the city. And just for good measure, there's a caviar service. Among all of this decadence, you'll find oysters on the half shell, king crab legs with drawn butter, peel-and-eat shrimp, barely opaque ceviche, scallops seared to toasty precision, and something called tilefish, served with popcorn. You'd need an ocean to contain it all. Or at least an ambitious restaurant bursting at the seams with brine, bumping up against Loring pond, pretending not to be landlocked.