The Hudson Transparencies

The photographs here complement those in: Wootton, Robin (2011), ‘The Hudson Transparencies. A set of remarkable visual aids by a distinguished Victorian microscopist.’ Report and Transactions of the Devonshire Association 143 pp. 61–90, where the transparencies are catalogued for the first time and twenty are illustrated.

Charles Thomas HudsonCharles Thomas Hudson MA, LLD, FRS (1828–1903) was a Bristol schoolteacher, a President and Honorary Fellow of the Royal Microscopical Society and a world authority on the Rotifera, a phylum of tiny multicellular animals in fresh water and marine ecosystems. With P.H. Gosse he coauthored the definitive 19th Century monograph ‘The Rotifera, or Wheel Animalcules’ published by Longmans Green & Co in 1886 and 1889. He retired to Dawlish in 1891 and then to Shanklin, Isle of Wight.

The 58 transparencies, in the possession of the University of Exeter, were created by Hudson to illustrate his lectures. Each is c. 96 cm high by 76 cm wide, and designed to be illuminated from behind in a darkened room. They may be unique.

The list on this page is an abbreviated version of that in the paper, q.v. for more detail. The names in quotes are those on Hudson’s labels; the others are the current names.

You can click on the images below to see larger versions.


Rhizopoda and Actinopoda

RJW1 “Amoeba princeps, Actinophrys sol, Raphidiophrys viridis”.


RJW2. “Acanthocystis turfacea” – with ingested rotifer.


RJW3. “ Lithoptera mülleri”.


RJW4. “Dictyocerus”. A radiolarian.



RJW5. “Carchesium polypinum”.


RJW6 “Opercularia nutans, Xanthidium armatum Ralfs. Stichotricha remex (Hudson)”.S. remex is now Chaetospira remex (Hudson, 1875). Xanthidium is a desmid.




RJW8 “Staurastrum, Closterium turgidum, Euastrum oblongum, Micrasterias, Staurastrum?, Penium interruptum”.



RJW9 “Batrachospermum proliferum”.



RJW10 “Ranunculus aquatilis with nymphs of Hydrachna & Nepa cinerea”.




RJW11. Unlabelled sponges..



RJW12. “Acyclus inquietus”.


RJW13. “Anurea…… ”. Species is unclear on the label.


RJW14. “Apsilus lentiformis”. Now Cupelopagis vorax Lenty, 1857. With Stentor, a large sessile ciliated protist.


RJW15. “Asplanchna Ebbesbornii A. Female B Male.” The specific name ebbesbornii does not appear in Seger’s checklist.


RJW16. “Asplanchna Ebbesbornii Contractile vesicle”.


RJW17. “Chonochilus volvox.


RJW18. “Euchlanis triquetra”. Also shows a desmid, and what may be Lacrymaria olor, a curious ciliate with a long ‘neck’


RJW19. “Floscularia campanulata Male”. Now Collotheca campanulata (Dobie, 1829).


RJW20. “Floscularia Hoodii”. Now Collotheca hoodi (Hudson, 1833).


RJW21. “Floscularia Longicaudata”. Now Collotheca campanulata.


RJW22. “Floscularia Mira”. Now Collotheca ornata (Ehrenberg, 1832).


RJW23. “Floscularia mutabilis. Young male & female”. Now Collotheca mutabilis (Hudson, 1885).


RJW24. “Hexarthra platyptera”.


RJW25. “Limnias Annulatus”. Now Limnias melicerta Weisse, 1848.


RJW26. “Limnias ceratophylli”.


RJW27. “Limnias ceratophylli”.


RJW28. “Melicerta ringens. A group of young”. Now Floscularia ringens (Linnaeus, 1758).


RJW29. “Melicerta ringens on hornwort”. Hornwort is Ceratophyllum.


RJW30. “Notommata Werneckii”. Now Proales werneckii (Ehrenberg, 1834).


RJW31. “Oecistes intermedius. do: longicornis”. Now Ptygura intermedius (Davis, 1867) and P. longicornis (Davis, 1867).


RJW32. “Pedalion mirum. A. Female. B. Male”. Now Hexarthra mira (Hudson, 1871).


RJW33. “Pterodina valvata (Hudson), Trachelocerca olor, Pediastrum NapoleonisPterodina valvata is now Testudinella patina (Hermann, 1783). T. olor is now Lacrymaria olor Müller, a ciliated protest. Pediastrum is a desmid.


RJW34. “Sacculus viridis”. Now Ascomorpha ecaudis Perty, 1850.


RJW35. “Stephanoceros Eickhornei”.


RJW36. “Synchaeta pectinata”.


RJW37. “Trochosphaera aequatorialis”.


RJW38. Unlabelled. Dr Hendrik Segers has identified them as follows. Centre: two Seison sp. Left bottom: a Colurella sp. Left top: a Dicranophoridae, probably Encentrum. Right bottom: a Synchaeta sp. Right centre: Brachionus sp. Top: Testudinella sp., (either T. clypeata or T. elliptica). Seison is an aberrant rotifer, parasitic on a small crustacean, Nebalia.


RJW39. Unlabelled. Dr Segers identifies them as: (top right and lower left) two Macrochaetus collinsi dorsal and lateral views; and three illustrations of Beauchampiella eudactylota; one dorsal, swimming; one lateral and one dorsal, contracted view.



RJW40. “Nais (or Proto) digitata. In the old tubes of Alcyonella stagnorum”. N. digitata is now Dero digitata Müller.


Arthropoda: Crustacea

RJW41. “Unknown zoeae”.


RJW42. “Zoea of Crab. Megalope of Galathea (?)”.


Arthropoda: Acarina

RJW43. “Atax histrionicus, Hydrachna geographica, Eylais extendus, Nymphs of Hydrachna globula, larva of Diplodontus filipes do. of Hydrachna globula”.


Arthropoda: Insecta

RJW44. “Larva of Ephemera or Day-Fly”.


RJW45. Unlabelled larva and adult of a caddis (Trichoptera).


Mollusca: Nudibranchia

RJW46. “Eolis Coronata”.


RJW47. “Thecacerca pennigera. Spawn: Eolis Drummondii. Spicules: Thecacerca pennigera. Doris aspera. Larvae of Doris tuberculata”.


RJW48. “Thecacerca pennigera”.


Mollusca: Cephalopoda

RJW49. “(Sepiola) Rossia owenii ?”. This appears to be three views of a Rossia, probably R. macrosoma, in different stages of colour change.


Bryozoa (Ectoprocta)

RJW50. “Microporella ciliata”. Only skeletal material is visible; the zooids are presumably retracted.


RJW51. “Young of Microporella ciliata”.


RJW52. Unlabelled bryozoan, almost certainly Plumatella repens (Linnaeus, 1758).


RJW53. Unlabelled bryozoan 2. Another fresh water bryozoan, with pictures of larval stages and ‘statoblasts’: disc-like resting stages from which new individuals develop.



RJW54. Unlabelled. This is a free-swimming “sea-lily” (Crinoidea), probably Antedon. The weed seems to be a young Laminaria frond.


RJW55. “Antedon rosaceus. Comatula rosacea. Pseud-embryo”.


RJW56. “Antedon, Comatula”. Pentacrinus stages of Antedon.


RJW57. “Skeleton of larva of sea urchin”.



RJW58. Unlabelled. This may not even be an animal.