More than 400 members of the Rittenhouse clan, some from as far away as West Germany and England, gathered to share family gossip and history over the weekend at the tricentennial celebration of Wilhelm Rittenhausen's arrival in America. People hovered over genealogical charts, running their fingers down the litany of names, searching for descendents of Rittenhausen _ cousins, great-great-uncles, or half-remembered names first heard in childhood stories. Paul Monroe Rittenhouse of State College manned the genealogical tables, helping distant relatives fill in the blanks in their record books, noting marriages, births, deaths. ``We're here to fill in the voids'' of the family's history, he said. Although family members began tracing their ancestors more than 100 years ago, Paul Rittenhouse recently found a ``missing link'' in 19th-century documents from Lancaster County. Those documents added more than 3,000 families to the Rittenhouse lists, bringing the total, in this country, to 50,000 descendents of Rittenhausen. Charlotte Rittinghausen, of Mannheim, West Germany, came to visit friends at the celebration, which ended Sunday. She said her father is interested in the family history, but she wasn't until the American celebration. Ms. Rittinghausen said she is continually learning of family members in her country. Now she has more names to add to her Christmas card list. ``We are spreading all over,'' she said. Rittenhausen settled in Germantown, the country's first permanent German settlement, in 1688. He built a papermill in 1690 on the Monoshone Creek in Philadelphia and became the American colony's first papermaker. His name, itself a derivation of Rittinghausen, was changed erroneously by American clerks, according to Rittenhausen decendant Milton Rubincam of West Hyattsville, Md. Rubincam called the name change ``a peculiarity of Colonial times,'' when American immigrants were confronted by strange languages and names. ``It doesn't matter what your name is. It's fun for everybody to trace their roots,'' said one of two Donald Rittenhouses at the reunion. ``I've been doing research for 10 years, just to see where it goes,'' said the retired salesman and financial officer from Minneapolis.