Douglas Jerrold's sister, Jane Matilda (1) Jerrold known as Mary, daughter of  Samuel Jerrold (1743-1820) and his third wife, Mary Anne Reid, married William John Hammond (see the Hammond family  & Hammond family trees ) who was born in 1799 and died in 1848.
Their children were:

(1) Mary Ann Hammond. Born c. 14th December 1825 at Holy Trinity, Kingston-upon-Hull, Yorkshire.
(2) William John Hammond. Born c. 31st July 1827 at St. Peters, Liverpool.
(3) Jane Matilda Hammond. Born c.12th June 1829 at St. Peters, Liverpool.
(4) Maria Hammond. Born c. 25th March 1831 at St Michael-le-Belfry, York.
(5) Henry Holbrey Hammond. Born c.14th Oct. 1833 in Doncaster. See below.*
(6) Fanny Elizabeth Hammond. Born c.27th Sept. 1834 in Doncaster.
(7) Kate Hammond. Born c.1st July 1840 St. Clement Danes, London. Died 1902. See below#
(8) Robert Hammond
(9) Susanne Hammond. Born 5th October 1842. Christened 26th July 1843 at St. Peters, Liverpool.

*(5) Henry Holbrey Hammond (see above) married Elisa Suthers who was born in Peru.
Four children:
(1) Charles Hammond. Died in Argentina.
(2) Arthur Hammond.
(3) Elisa Hammond. Married Alexander Hyslop-Maxwell.
One child: Sandy Hyslop-Maxwell
(4) Henry Francis Hammond. Died after 1916. Married Alejandrina de Lavalle, born in Peru. Two sons:
(1) Alec Hammond
          (2) Henry J.Hammond. Born Valparaiso. Died after 1942. Married Cecilia Swayne 1942. Five children:
                (1) Anthony Hammond. Married Felice.
                (2) G.B.Hammond
                (3) Leslie Hammond
                (4) Peter Hammond
                (5) Richard Hammond

#(7) Kate Hammond (see above) married George Johnson Witter (1838-1885).  One daughter:
(1) Suzanne Mary Witter (1869-1953) married William Henry Constable (1868-1954). One son:
        (1) Stanley Preston Constable (1912-2001)