| Reference number | Title | Date |
| RR/2/265 | Referee's report by Arthur Farre, on a paper 'On the blood-proper and chylaqueous fluid of invertebrate animals' by Thomas Williams | 12 June 1852 |
| RR/3/286 | Referee's report by George Busk, on a paper 'Researches on the structure and homology of the reproductive organs of the annelids' by Thomas Williams | 10 January 1858 |
| RR/3/283 | Two letters from Thomas Williams, on his paper 'Researches on the structure and homology of the reproductive organs of the annelids' to the Secretary of the Royal Society | 20 June 1857 |
| RR/3/279 | Referee's report by George Busk, on a paper 'Researches on the structure and homology of the reproductive organs of the annelids' by Thomas Williams | 21 April 1857 |
| RR/3/281 | Referee's report by Henri Milne Edwards, on a paper 'Researches on the structure and homology of the reproductive organs of the annelids' by Thomas Williams | 16 April 1857 |
| EC/1858/16 | Williams, Thomas: certificate of election to the Royal Society | |
| RR/3/282 | Letter from George Busk, on a paper 'Researches on the structure and homology of the reproductive organs of the annelids' by Thomas Williams | 22 October 1857 |
| PT/75/7/5 | Drawing, 'Reproductive and segmental systems of Lumbricus jordanii' by [Thomas] Williams | [1856] |
| PT/75/7/15 | Drawings, segmental organs of various Annelids by [Thomas] Williams | [1856] |
| PT/75/7/4 | Drawing, 'Reproductive and segmental systems of Nais filiformis' by [Thomas] Williams | [1856] |
| PT/75/7/7 | Drawing, segmental organ of common earthworm by [Thomas] Williams | [1856] |
| PT/75/7/12 | Drawings, vertical section of segment of body of Nereis margaritacea by [Thomas] Williams | [1856] |
| PT/75/7/9 | Drawing, 'One of the segmental organs of Arenicola enlarged' by [Thomas] Williams | [1856] |
| PT/75/7/3 | Drawing, 'Segmental organ of Nais serpentina' by [Thomas] Williams | [1856] |
| PT/75/7/11 | Drawing, 'Two of the segmental organs of Terebella nebula [sic] enlarged' by [Thomas] Williams | [1856] |
| PT/75/7/14 | Drawings, Spio vulgaris and Nereis margaritacea by [Thomas] Williams | [1856] |
| PT/75/7/10 | Drawing, 'One segmental organ of leech enlarged' by [Thomas] Williams | [1856] |
| PT/75/7/8 | Drawings, reproductive organs of common earthworm by [Thomas Williams] | [1856] |
| PT/75/7/13 | Drawing, 'Aricia cuvieri' by [Thomas] Williams | [1856] |
| PT/75/7/19 | Drawing, 'Alimentary and reproductive systems of Aphrodita aculeata' by [Thomas] Williams | [1856] |
| PT/75/7/20 | Drawings, segmental organs of Polynoe semisquamosa and Aphrodita aculeata by [Thomas] Williams | [1856] |
| PT/75/7/16 | Drawings, segmental and reproductive systems of Chloraema dujardinii by [Thomas] Williams | [1856] |
| PT/75/7/18 | Drawing, 'Planaria' by [Thomas] Williams | [1856] |
| PT/75/7/17 | Drawings, segmental organs of various Annelids by [Thomas] Williams | [1856] |
| PT/75/7/6 | Drawing, segmental organs of Lumbricus kauii by [Thomas] Williams | [1856] |