Complex sentence: The membership of the Dáil was drawn from the Irish MPs elected to sit at the Westminister parliament, 105 in total, of which 27 were present as being present ("i láthair") for the first meeting.
Split into simpler sentences: The membership of the Dáil was drawn from the Irish MPs elected to sit at the Westminister parliament, 105 in total. Twenty-seven were present as being present ("i láthair") for the first meeting.