I thought Mervyn was one of three brothers, but it now seems he had a lot of half brothers and sisters. His father was one busy man , I feel a pity for his wife's
http://www.libraryireland.com/Pedigrees1/o-gorman-2-heremon.phpThe relevant section cut from this link is this
137. Edmond-Anthony O'Gorman, of Monamore, county Clare: second son of Michael-Arthur; b. 6th Oct., 1820, and living in 1881. He m. in Jan., 1856, Sophia Pereira (who died October, 1863), and by her had five children:
I. Joseph-Vincent, born 21st May, 1857; made his vows in the Society of Jesus, in London, July, 1877.
II. Francis-Edmond, born 17th November, 1859.
III. Ignatius-Thomas, born 31st July, 1860; in the Society of Jesus, 7th September, 1880.
IV. Mary-Alicia, d. an infant 1871.
V. Mary, born 11th Oct., 1863.
In 1865 he m. Ellen, daughter of Capt. Edward Whyte, R.N., of Loughbrickland, and by her (who died in Nov., 1867) had one son:
VI. Edmond-John Whyte.
In 1871 he m. Margaret Barclay, eldest daughter of Mervyn Archdall Nott Crawford (see the "Crawford" pedigree), of Millwood, county Fermanagh, and by her had three children:
VII. Mervyn Archdall, born 19th December, 1871.
VIII. Cecil Carleton Crawford, born 6th April, 1873.
IX. Bernardine Beauchamp-Colclough, born 1st Nov., 1874
Could one of these half brothers or sisters be the parent of Christina ?