| RefNo | Title | Date |
| EC/1931/14 | Spencer, William Kingdon: certificate of election to the Royal Society | |
| RR/48/16 | Second referee's report by William Kingdon Spencer, on a paper 'The lantern and girdle of some recent and fossil Echinoidea' by Herbert Leader Hawkins | [April 1934] |
| RR/18/183 | Referee's report by William Kingdon Spencer, on a paper 'Lapworthura: a typical brittlestar of the Silurian age; with suggestions for a new classification of the Ophiuroidea' by Igerna Sollas and William Johnson Sollas | July 1911 |
| NLB/44/397 | Copy letter from Robert William Frederick Harrison to W [William] K [Kingdon] Spencer | 4 July 1911 |
| NLB/44/361 | Copy letter from Robert William Frederick Harrison to W [William] K [Kingdon] Spencer | 27 June 1911 |
| RR/20/134 | Referee's report by Francis Arthur Bather, on a paper 'The evolution of the cretaceous asteroidea' by William Kingdon Spencer | 8 February 1913 |
| RR/20/135 | Referee's report by John Walter Gregory, on a paper 'The evolution of the cretaceous asteroidea' by William Kingdon Spencer | 21 March 1913 |
| NLB/73/64 | Copy letter from Francis Alexander Towle, Assistant Secretary of the Royal Society; to Dr. [Francis Arthur] Bather, FRS | 14 November 1930 |
| RR/58/68 | Referee's report by William Dickson Lang, on a paper 'Two new Echinoidea, Aulechinus and Ectinechinus, and an adult plated holothurian, Eothuria, from the Upper Ordovician of Girvan, Scotland' by Ernest William MacBride and William Kingdon Spencer | 31 March 1937 |
| RR/43/135 | Referee's report by William Kingdon Spencer, on a paper 'The development and function of the heart and pericardium in echinodermata' by Nidambur Narasimhamurti | June 1931 |
| RR/48/12 | Referee's report by William Kingdon Spencer, on a paper 'The lantern and girdle of some recent and fossil Echinoidea' by Herbert Leader Hawkins | [February 1934] |
| RR/64/112 | Referee's report by Herbert Leader Hawkins, on a paper 'Two new Echinoidea, Aulechinus and Ectinechinus, and an adult plated holothurian, Eothuria, from the Upper Ordovician of Girvan, Scotland' by Ernest William MacBride and William Kingdon Spencer | [October 1937] |
| RR/64/113 | Referee's report by William Dickson Lang, on a paper 'Two new Echinoidea, Aulechinus and Ectinechinus, and an adult plated holothurian, Eothuria, from the Upper Ordovician of Girvan, Scotland' by Ernest William MacBride and William Kingdon Spencer | 10 Septmber 1937 |