Career
He specialized in the Tunicata, and in gastropods. (October 1851). "Descriptions of two new species of nudibranchiate Mollusca, one of them forming the type of a new genus". Annals and Magazine of Natural History (series 2)8(46): 290-302, pls.
9-10.
Alder, Joshua, Embleton, Dennis, Hancock, Albany, Hopkinson, John,Norman, Alfred Merle, 1905-1912 The British Tunicata. An unfinished monograph, by the late Joshua Alder and the late Albany Hancock. Edited by John Hopkinson, with a history of the work by the Review
A. M. Norman.London,Printed for the Ray society.
Names or synonyms of tunicates described by Joshua Alder include: Dicoryne conferta (Alder, 1856) Eudendrium capillare Alder, 1856 Hydractinia areolata Alder, 1862 Corymorpha nana Alder, 1857 Campanularia hincksii Alder, 1856 Laomedea flexuosa Alder, 1857 Laomedea neglecta Alder, 1856 Halecium nanum Alder, 1859 Taxa of gastropods described by Joshua Alder include: Polyceroidea Alder & Hancock, 1845 Fiona Alder & Hancock, 1851 Chromodoris Alder & Hancock, 1855.