| Reference number | Title | Date |
| EC/1894/14 | Lydekker, Richard: certificate of election to the Royal Society | |
| RR/17/113 | Referee's report by Richard Lydekker, on a paper 'On the skull, mandible, and milk dentition of Palæomastodon, with some remarks on the tooth change in the proboscidea in general' by Charles William Andrews | 9 July 1907 |
| NLB/14/495 | Copy letter from an unknown correspondent, to Messrs Harrison & Sons | 20 November 1897 |
| NLB/4/995 | Copy letter from Herbert Rix, to Richard Lydekker, The Lodge, Harpenden, Hertfordshire | 16 December 1890 |
| NLB/10/740 | Copy letter from Theodore E James, to Messrs Harrison & Sons | 29 January 1895 |
| NLB/10/53 | Copy letter from Herbert Rix, to Richard Lydekker, Fellow of the Royal Society | 19 September 1894 |
| NLB/10/766 | Copy letter from Theodore E James, to Messrs Harrison & Sons | 1 February 1895 |
| NLB/10/744 | Copy letter from Herbert Rix, to Richard Lydekker, Fellow of the Royal Society | 29 January 1895 |
| RR/16/4 | Referee's report by Richard Lydekker, on a paper 'On the evolution of the Proboscidea' by Charles William Andrews | 28 March 1903 |
| RR/16/25 | Referee's report by Richard Lydekker, on a paper 'Reptilian remains from the Trias of Elgin' by George Albert Boulenger | June 1903 |
| RR/16/113 | Referee's report by Richard Lydekker, on a paper 'An account of the Devonian fish Palaeospondylus gunni, Traquair' by William Johnson Sollas and Igerna Briinhilda Johnson Sollas | June 1903 |
| RR/16/145 | Referee's report by Richard Lydekker, on two papers 'On the ossiferous cave-deposits of Cyprus' and 'Further note on the remains of Elephas cypriotes from a cave-deposit in Cyprus' by Dorothea Minola Alice Bate | 23 May 1904 |
| NLB/39/292 | Copy letter from John Rose Bradford to The Under Secretary of State for India | Undated |
| EC/1894/15 | Lydekker, Richard: certificate of election to the Royal Society | |
| NLB/51/274 | Copy letter from Robert William Frederick Harrison, Assistant Secretary of the Royal Society to Richard Lydekker FRS | 1 February 1915 |
| NLB/3/1012 | Copy letter from Herbert Rix, to Professor William Henry Flower, Fellow of the Royal Society | 11 December 1889 |
| NLB/35/663 | Copy letter from Robert William Frederick Harrison, to Richard Lydekker, Fellow of the Royal Society | 27 June 1907 |
| RR/17/400 | Referee's report by Richard Lydekker, on a paper 'The possible ancestors of the horses living under domestication' by James Cossar Ewart | 3 June 1909 |
| RR/17/4 | Referee's report by Richard Lydekker, on a paper 'Elephant remains from Crete with description of Elephas creticus Sp.Nov.' by Dorothea Minola Alice Bate | 5 January 1907 |
| RR/15/12 | Referee's report by Richard Lydekker, on a paper 'The distribution of vertebrate animals in India, Ceylon & Burma' by William Thomas Blanford | 4 January 1901 |
| PP/17/2 | Paper, 'On the generic identity of Sceparnodon and Phascolonus' by R [Richard] Lydekker | 1890 |
| RR/13/118 | Referee's report by Richard Lydekker, on a paper 'Researches on the structure, organisation, and classification of the fossil reptilia. Part X. On the complete skeleton of an anomodont reptile (Aristodesmus Rütimeyeri, Wiedersheim), from the bunter sandstone of reihen, near basel, giving new evidence of the relation of the anomodontia to the monotremata' by Harry Govier Seeley | 7 January 1896 |