190 
NOTE ON CYSTIDICOLA FARIONIS FISCHER. A THREAD¬ 
WORM PARASITIC IN THE SWIM-BLADDER OF A TROUT. 
By A. E. SHIPLEY, M.A., Hon. D.Sc. (Princeton), F.Pt.S., 
Fellow and Tutor of Christ’s College, Cambridge. 
CYSTI DICOLA FARIONIS. G. Fischer, 1798. 
Synonyms : Fissula farionis. Bose, 1802. 
Fissula cystidicola. Lamarck, 1801. 
Ophiostoma cystidicola. Rudolphi, 1809. 
Spiroptera cystidicola. Rudolphi, 1819. 
Dispharagus cystidicola. Dujardin, 1845. 
Ancyracanthus cystidicola. Schneider, 1860. 
Ancryacanthus cystidicola. von Linstow, 1878. 
Some hundred and ten years ago, Dr Gotthelf Fischer, in a commu¬ 
nication dated from Vienna, described a Nematode living in the swim- 
bladder of the trout. He named this worm Cystidicola farionis and his 
description is accompanied by some rough cuts. Bose (1802) re-described 
the same Nematode under the name Fissula farionis. The same worm 
was again described by Rudolphi (1819) under the name Spiroptera 
cystidicola. Dujardin (1845) mentions it under the name Dispharagus 
cystidicola. Later it was removed by Schneider (1860) from the genus 
Spiroptera and placed in Diesing’s genus Ancyracanthus. von Linstow 
uses this generic name “with a difference”; he spells it Ancryacanthus. 
Ramsay Wright (1879) records the species from Salmo siscowet 
Agassiz. It is widely spread on the continent of Europe and is now— 
I think for the first time—recorded in England. 
Mr R. T. Leiper of the London School of Tropical Medicine, who 
kindly examined some specimens of these round worms which I hail 
recognized as belonging to Schneider’s species A. cystidicola , has pointed 
out that the worms were originally described and figured by G. Fischer 
and that his name Cystidicola farionis still stands. Mr Leiper has 
written a note on the anatomy of the worm and his description follows 
(see p. 193). 
