Thomas Wallis McDonald was Surgeon Superintendent on two convict ship voyages to Australia: Hindostan to Van Diemen's Land in 1839 and Lord Lyndoch to Van Diemen's Land in 1841.
Assistant Surgeon on H.M.S. Conflict, West Africa
Appointed Surgeon 9 November 1830
Appointed to H.M.S. Brisk at the Cape of Good Hope and Coast of Africa in 1834.
Appointed to the Phoenix Steam Vessel on 9 September 1835. 
Appointed Surgeon H.M.S. Belle Isle 1844 -45
Appointed Surgeon Hibernia in the Mediterranean 1845-8
Appointed Surgeon on Royal Yacht Victoria and Albert 1848
Deputy Inspector General of Hospitals and Fleets 19 July 1854 
Medical Register 1865
Deputy Inspector General of Hospitals and Fleets. Mem. 1824, Fell. 1844, Royal College Surgeons, England
Thomas McDonald married Jane Fox who died at Gosport on 27 May 1860 . He is included in the genealogy of Jane's family (1872):
Jane Fox, married Thomas Wallis McDonald, Surgeon R.N., now Inspector-General R.N. (who married, secondly, Louisa, widow of Lieutenant C. B. Baskervüle, R.N.), and had issue -
i. Wallis McDonald, surgeon.
i. Anna McDonald, died s. p.
ii. Mary Tabor McDonald, married to William Ayre, Surgeon R.N., no issue.
iii. Frances Fox McDonald married to John Holland, Major Royal Marines, and has issue - Charles Theodore Holland, and a daughter born 2 January, 1872.
iv. Flora McDonald, married to Charles Kealy, and has issue, Mary Kealy.
Thomas Wallis McDonald died 1 April 1884 at Teignmouth, England
2). McDonald-Pogson - On July 2 at St. John's Church, River Ouse, Tasmania, Wallis McDonald M.R.C.S. Eng., L.R.C.P. Edin, only son of T.W. McDonald, Esq., Inspector-General of Hospitals and Fleets, Teignmouth, Devon, to Jane Anna Louisa, second daughter of the late George Thomas Pogson Esq., Rotherwood, Tasmania. - Medical Times and Gazette 7 September 1872