Graduate students using the Harkness Common grill are paying for their purchases there with a special type of coupons this year, because undergraduates last year crowded into the grill, sometimes using normal University coupons to illegally buy beer.

"Undergraduates had no right to use the Harkness grill," William A. Heaman, manager of dining halls, said yesterday. "They are supposed to use the Eliot House grill instead, and we had to stop their use of Harkness."

Black Stripe Employed

The graduate coupons this year have been distinguished by a heavy black stripe and are sold only to graduate students. Except for the stripe the coupons are the same as those sold in the College.

Undergraduates who wish to eat at the Common now may do so only as the guests of graduates.

Frequent complaints were registered last year by graduates who objected to College students crowding into the Common, which serves snacks as well as beer at reasonable prices.

The complaints came principally because of this crowding, rather than from objectors to the sometimes illicit purchase of beer. "This is certainly one thing we have tried to prevent with the new coupons," Heaman added.

The Eliot grill, which also serves sandwiches and other snacks, but not beer, is open daily except Saturday until midnight, and is designed for the use of all undergraduates. All purchases there, like Harkness, must be made by coupon.

The University also operates a grill across the river at the Business School.