Civil rights attorneys asked the federal court here today to abolish at-large municipal voting systems in three heavily black Eastern Shore towns, contending that they effectively prevent blacks from winning local elections.

In lawsuits filed against the towns of Easton, Snow Hill and Princess Anne, the attorneys said at-large voting, in which all residents of the town vote on all the city council candidates, dilutes black electoral power in violation of the federal Voting Rights Act. The lawyers said they are seeking instead the establishment of district elections, in which voters choose only those council members representing their district.

Although the towns' black populations range from 28 to 40 percent, only one black candidate has won a council seat in any of the towns in the past 50 years, according to the lawsuits.

"These lawsuits will end the antiquated, outdated apartheid system" of the small quiet county seats of Talbot, Somerset and Worcester counties, said Maryland civil rights activist Carl Snowden at a press conference here. "They will end of the good ol' boy system."

Apartheid is the system of racial separation enforced in South Africa.

The suits follow a similar action against Annapolis last winter. That case ended in an out-of-court settlement in which Maryland's capital city agreed to abolish citywide elections and create eight electoral districts, two of them with black populations of 65 percent or more, according to Snowden.

Today's actions are not the first to challenge alleged racial discrimination on Maryland's Eastern Shore, a largely rural area that civil rights activists have likened to the Deep South.

Parts of the Eastern Shore have a long history of racial discord. Cambridge, seat of Dorchester County, underwent 14 months of martial law in the early 1960s after a series of black protests. Fires and riots triggered more martial law in 1967 and the county courthouse was bombed in 1968 when activist H. Rap Brown was to go on trial there.

The U.S. Justice Department sued Dorchester County and Cambridge last year, alleging that at-large elections there discriminated against blacks. County Attorney Thomas Merryweather said today that the county is negotiating a settlement that would include district elections. Cambridge Town Council president Edward E. Watkins said that the case against the city is "still in litigation . . . but we're working toward a settlement."

In addition, the Maryland attorney general's office surveyed 11 counties late last year that have at-large elections and a 10 percent or greater black population to see if there is any pattern of racial discrimination in voting. A report on the findings of that survey is expected next month.

C. Christopher Brown, a Baltimore civil rights attorney, who with fellow lawyer Alan Hillard Legum of Annapolis, filed the suits today on behalf of black voters in the three Eastern Shore towns, said additional suits against other towns "may be down the road."

Brown said he hopes the towns will each negotiate a settlement, like Annapolis, to avoid protracted litigation in court.

News of the lawsuits was greeted today by officials in Easton, Snow Hill and Princess Anne with a mixture of surprise and puzzlement.

"That's news to me," said Princess Anne Town Solicitor Logan C. Widdowson. "We've never had any complaints." For that matter, he said, "We've never had a black to file for public office since at least 1972 when I became city attorney."

Town Manager Wallace Dashiell said, "There's been no discrimination here . . . . We have a very good rapport with our black people."

Snow Hill Town Manager Douglas Miller noted that one black candidate won a council seat in 1979 and served a two-year term. "I don't think the suit's claim is a valid one," he said.

Mayors of the three towns declined to comment on the suits or could not be reached today.

The lawsuits contend that at-large elections dilute the black vote and assure that white candidates in the "racially polarized" towns will almost always win at the polls over black candidates.

Also, attorney Brown said today, the suit seeks to end requirements in all three towns for "dual registration" -- separate registration for municipal elections and for state and federal elections -- which creates an "additional burden" for blacks in areas where whites historically have out-registered blacks and where blacks have been discouraged from voting.

In the same way, he said, Easton and Snow Hill have staggered elections, with only one or two seats up for grabs each election year, making it difficult for blacks to "concentrate all their energy" on one candidate as they would if all candidates ran simultaneously.

In Princess Anne (population: 1,499), Town Manager Dashiell said, "I don't know how we'd go to districts here . . . . The town is two square miles and only has about six blocks."

Said solicitor Widdowson, "I guess Mr. Brown . . . doesn't have anything better to do than come across the Bay Bridge and tell us folks on the Eastern Shore how to live."