London - Veteran Australian lock Mark Chisholm and fellow second row forward Cornelius van Zyl of Italy were on Monday called up to the Barbarians squad for their upcoming three match tour.
Other additions since the provisional squad was announced last week are Casey Laulala, Heinke van der Merwe, Francois Louw and Ernst Joubert.
Among those sidelined by injury are Stephen Jones and Schalk Brits.
The tour opener against England on 27 May at Twickenham is followed by clashes with Ireland in Gloucester on May 29 and Six Nations Grand Slam champions Wales at the Millennium Stadium on June 2.
The Barbarians defeated all three countries in their most recent fixtures against them.
Isa Nacewa (Fiji), Mils Muliaina (New Zealand), Ian Balshaw (England), Cedric Heymans (France), Shane Williams (Wales), Paul Sackey (England), Sailosi Tagicakibau (Samoa), Casey Laulala (New Zealand), Mike Tindall (England), Damien Traille (France), Felipe Contepomi (Argentine), Stephen Donald (New Zealand), Rory Lawson (Scotland), Jerome Fillol (France)
Benoit August (France), John Smit (South Africa), Aled de Malmanche (New Zealand), John Afoa (New Zealand), Duncan Jones (Wales), Neemia Tialata (New Zealand), Heinke van der Merwe (South Africa), Mark Chisholm (Australia), Mick O'Driscoll (Ireland), Anton van Zyl (South Africa), Pelu Taele (Samoa), Cornelius van Zyl (Italy), Raphael Lakafia (France), Akupusi Qera (Fiji), John Beattie (Scotland), Pedrie Wannenburg (South Africa), Ernst Joubert (South Africa), Francois Louw (South Africa)