Fifteen people, including five Harvard students, were arrested in Harvard Square yesterday afternoon for selling Avatar. The arrests brought to at least 49 the number of people who have been seized by Boston or Cambridge police for peddling the nine-month-old newspaper.

Those taken into custody yesterday were charged with selling obscene literature. Conviction carries a penalty of up to two years in jail and a fine of $100 to $1000.

All but two of the 15 elected to spend the night at the Central Square lock-up, although a bonding commissioner said they could pay a $3-dollar fee and leave on their own recognizance. They are scheduled to be arraigned this morning in the Third District Court of Eastern Middlesex.

Yesterday's arrests came in two round-ups. In the first, at 2:10 p.m., nine men and a young girl who police said was a juvenile were packed into a paddy wagon in front of Holyoke Center and taken to the Central Square station. The ten had been selling the paper to passers-by along Massachusetts Avenue for less than 90 minutes.

Numbing 30-degree temperatures and a brisk wind made it seem longer, however, and some vendors looked almost relieved by the time two uniformed patrolmen and two plainclothesmen arrived to take them away. They had sold about 300 papers.

The Harvard students arrested yesterday were Jacob S. Egan '68; Lewis S. W. Crampton, a third-year graduate student; Jesse Kornbluth '68, whose anthology of articles from underground newspapers is scheduled to be published by Viking Press later this year; his brother, Richard S. Kornbluth '69; and Stephen D. Lerner '68, former executive editor of the CRIMSON.

Within two hours, arresting officers returned to the station with five more prisoners. The new arrivals were greeted with a jovial cheer from the first group, which was still being processed by police.

Meanwhile, a half dozen more disconsolate Avatar staffers waited in the lobby of the police station for bond to be set and for the prisoners to decide whether they wanted to come out.

"It was a joke the first few times they arrested somebody," said Wayne M. Hansen, who is listed on the masthead as one of the Avatar's two editors. "But now it's really beginning to tell. If we don't get support, if people from Harvard and places like that don't come out and sell papers for us, we're going to go under."

He said that Avatar would sell papers in front of Holyoke Center again this afternoon, and that if there were more arrests, staff members would stage a candle-light protest demonstration later in the evening outside the Central Square police station.

"We're going to send more and more people to sell papers until someone else does something about it [the arrests] or until we're all in jail and we can't do anything about it ourselves," he said.

The trim, soft-spoken Hansen, gazing intently from behind rimless glasses, said he would not consider eliminating from the paper's standard vocabulary the four-letter words and sexual allusions that have stirred the ire of two Cambridge mayors, the police, and Governor John Volpe.

"It's philosophically impossible," he said. "That would make me as guilty as the police are, as far as I'm concerned. We're not fighting for freedom of obscene expression. When those words occur, it's because we feel they communicate what we're trying to say."

Hansen said that Avatar has paid out more than $225 in bail since last Saturday, when nine others were arrested for selling the paper. "To us, it's a lot," he said. "We're down to the wire."

According to Hansen about 50 people, 15 of them children between the ages of three months and ten years, are supported by Avatar. They live in a small, tightly knit community on Fort Hill in Roxbury. "We have four houses and ten apartments," said Hansen. "It's a very tight thing, like a family. It works out because everybody cares enough about everybody else."

Most of the 35 adults earn all or part of their living selling the Avatar, keeping about half of the 35 cents they get on each sale. Some, including Jim Kweskin, leader of the "jug band" which bears his name, have other sources of income. Nine or ten work full-time putting out the paper, Hansen said.

"It varies," said Hansen. "Sometimes people are full-time. Sometimes they're not. But all of our livelihoods are resting on this paper."

He said that he did not think of the one-and-a-half-year-old group as hippies, though "we're more like that than anything else. We just want to show people another way to live together."

Avatar staffers claim that the paper, which is published every two weeks, has a circulation of 22,000.

A number of vendors have apparently been attracted by the notoriety that the paper has received from the arrests, which began three months ago. Only four of those arrested yesterday gave Roxbury addresses.

"They must go out and recruit people for a day," sighed one police official. "Every time we clear out one group, we go right back and find some more selling it."

"I don't understand why they do it," he added, pointing to an article in the current issue, Avatar's 18th, containing a series of graphic epithets. "There's no point in writing like that. You wouldn't want your kid sister reading that."

So far, according to attorneys for the 49 who have been arrested, four have been acquitted on the grounds that they did not actually sell the paper. None of the others have been tried. The first 14 who were arrested have been indicted by a grand jury and will be tried in Middlesex County Superior Court, but no date has yet been set