sentences:  The two-member constituency was abolished for the 1918 general election.A single-member constituency (known as Merthyr) existed from 1918 until 1945 and, by the 1950 general election, it had been renamed Merthyr Tydfil.The constituency was abolished for the 1983 general election, when it was largely replaced by the new Merthyr Tydfil and Rhymney constituency.