The state of dining in many museums is disappointing. You're part of a captive audience. What a pleasure, then, to know that after you've strolled the goldfish ponds and other loveliness of the Morikami's gardens, some fine and affordable Japanese food is waiting at Cornell, which overlooks all the flora and babbling brooks. Start with the seaweed salad, a plentiful plate mixed with sesame seeds and mild hot peppers in a vinaigrette sauce for $4.50. Tuna, shrimp, grouper, and salmon rolls run $4.50 to $5.50. But it's the luncheon specials that make the day. For the budget-minded, the beef bowl, at $6.95, is a meal in itself, with strips of stir-fried beef, onions, fresh mushrooms, and carrots. Jumbo shrimp in Asian leek sauce is a steamed delight that includes rice and vegetables for $8.95. For vegetarians, there's Asian eggplant with garlic sauce for $6.95. For the true Japanophile, there's the eel bowl, in which this favored seafood is baked in sauce and ladled over rice. Cornell is open from 11 a.m. to 3 p.m. Tuesday through Sunday. Admission into the museum is $9 for adults, $8 for seniors, and $6 for kids.