There appears to be no reference to the mrge of a Thomas Hitchings to a Catherine Evans in 1855 in England or Wales.
An Esther Hitchings was born in one of the parishes or chapels listed under the Pontypridd Registration District in 1873 (see Free BMD).
There is no Thomas Hitchings baptized in Pembrokeshire in 1835, the nearest are as follows ;
From my transcription of the Parish Registers of Pembroke St Michael 1711 to 1930’s I note;
20 Mar 1833 Thomas to John & Sarah Hitchings of Pennybridge a Servant baptized by James Dalton.
Note ; John Hitchings of Pembroke St Michael had mrd Sarah Davies at Narberth on the 31 January 1832.
Martletwy Baptism Register
Thomas to John & Hannah Hitchins (no ‘g’) baptized on the 26 Nov 1837
Note John Hitchins mrd Hannah Phillips at Martletwy on the 05 Dec 1818
IGI notes that your family of Thomas & Catherine Hitichings reside at Ystradyfodwg Glamorganshire in 1881 along with children Henry, Thomas, Catherine Jane, Alice, Esther, Evan William, Alfred John, & Margaret.
In 1881 Thomas is noted as born in Narberth in abt 1836, either of the above entries could fit "your" Thomas, but a little more work on census, wills etc, should resolve which is yours
Owen Ap Benfro