This is another family of double descents. The unusual thing here is that the cousins (in this case half first cousins) shared the same surname. That's always interesting.
1. William Clapp born say 1500 in Devonshire, England, died July 1555 at Harford, Devonshire. He married about 1525 to Alice (---) who was living in 1555. They had six children: Richard, Florence, Gyllian, Alice, Beaton and Joahanne.
2. Richard Clapp born about 1528 at Sidbury, Devonshire, died before July 1609 there. He married first a woman whose name we don't know. He married secondly about 1568 Christian (---) who died at Sidbury about August 1609. By his first unknown wife, Richard had six children: an unnamed child, another unnamed child, Peter, Robert, Mary, and William. Richard and Christian had three children: Nicholas, Eyde, and a daughter.
3a. William Clapp born Sidbury about 1565 died 1 March 1640/1 Salcombe Regis, Devonshire. He married at Sidmouth, Devonshire 11 September 1593, Johan Channon, born about 1570 and died 5 August 1629 at Salcombe Regis, daughter of Robert and Johan (---) Channon. They had seven children, many of whom came to New England: Jane, William, Robert, Edward, John, Roger, and Sarah. Of those Jane, Edward, Roger, and Sarah all came to New England. In addition Sarah married her half first cousin Nicholas Clapp.
3b. Nicholas Clapp born Sidbury about 1570 and died at Venn Ottery, Devonshire on 14 March 1631. He married there about 1602 Elizabeth (---) who died there 24 March 1631. Nicholas and Elizabeth had ten children: Richard, Prudence, Jane, Thomas, a daughter, Nichoals, Barbara, Radigone, John, and Ambrose. Of these, Prudence, Thomas, Nicholas, Barbara, Radigone, and John all came to New England.
4. Edward Clapp, son of William and Johann (Channon) Clapp was born about 1609 at Salcombe Regis, Devonshire and died 8 January 1664/5 at Dorchester, Massachusetts. He married his half first cousin before 1630, Prudence Clapp, born about 1606 at Sidbury and died before 1646 at Dorchester, daughter of Nicholas and Elizabeth (---) Clapp. Edward married secondly about 1646 Susanna Cockerill who died at Dorchester 16 June 1688, daughter of William and Elizabeth (---) Cockerill of Salem, Massachusetts. Edward migrated in 1635 on the ship Hopewell. Edward and Prudence had three children: Elizabeth, Prudence, and Ezra. Edward and Susana had an additional eight children: Nehemiah, Susana, William, Joseph, Esther, Abigail, Joshua, and Jonathan.
5. Ezra Clapp was born 22 May 1640 at Dorchester and died 23 January 1718/9 at Milton, Massachusetts. He married about 1666 Abigail Pond, who died at Milton 12 October 1682, daughter of William and Mary (Dyer) Pond.* Ezra married secondly on May 22, 1684 Experience Houghton who died at Milton on 17 December 1717, daughter of Ralph Houghton. Ezra and Abigail had seven children: Mary, Edward, Ezra, Abigail, Sarah, Judith and Elizabeth. Ezra and Experience had eight more children: William, Jane, Mindwell, Nehemiah, Ezra, Ebenezer, Hester and Susanna.
6. Elizabeth Clapp born 1 October 1682 at Dorchester, died 4 December 1705 at Sudbury, Massachusetts. She married at Sudbury on 13 March 1700, John Rice (Jr.) born at Sudbury 29 September 1675 and died there 28 July 1733, son of John and Tabitha (Stone) Rice. John married secondly Sarah Frost, daughter of Thomas Frost who died in 1717. John married thirdly in 1731 Sarah Dunton who survived him and died in 1739. John and Elizabeth had three children: Comfort, Abigail, and Elizabeth. John and Sarah had seven additional children.
* Please note that Anderson in the Great Migration does not give Abigail's name as Pond and notes there is no evidence for such an identification. He asks for proof of this relationship. He also rearranges the children of Edward and Prudence giving them only three children. This is the most up-to-date treatment of the family.
Ancestry of John Harrington Stevens & His Wife Frances Helen Miller by Mary Lovering Holman and Winifred L. Holman (2 vols. 1948-1952), p. 276-80.
The Great Migration: Immigrants to New England 1634-1635 by Robert Charles Anderson, George F. Sanborn, Jr., and Melinde Lutz Sanborn (Boston, NEHGS, 2001), II:76-81.
The Clapp Memorial by Ebenezer Clapp (Boston, 1876).
Genealogical History of the Rice Family: Descendants of Deacon Edmund Rice by Andrew Henshaw Ward (Boston, 1858).