292 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



The writer does not think that the rearing of oysters from artificially 

 impregnated eggs will ever be a profitable business, in that it is likely 

 that collecting spat by simple and inexpensive methods, such as the 

 use of brush, shells, gravel, and other cheap, clean materials, will 

 always yield as good results on a large scale as any artificial method 

 could possibly give. But it is possible that we greatly underestimate 

 the value of wholly artificial methods. 



NOTICE OF A PARASITE OR COMMENSAL OF THE OYSTER, WITH 



REMARKS ON ITS DISTRIBUTION. 



About a year since, M. Adrien Certes, of 21 Eue de Jouy, Paris, 

 announced, through the pages of the Bulletin of the Zoological Society 

 of France, that he had met with an organism inhabiting the stomach and 

 intestines of the oyster, which presented some remarkable characteris- 

 tics, and which was allied to a parasite found in the blood of the frog, 

 and to another species found in the intestines of birds. 



The writer first noticed this creature in the stomach and intestines of 

 the American oyster during the summer of 1880, and then supposed it to 

 be nothing more than a small vegetable organism allied to Vibrio, and has 

 made some allusion to it under that name in his report to the Maryland 

 Commissioner for that year. 



M. Certes has since shown that this identification is an error, as well 

 as a later name which the writer had proposed, namely, Spirillum ostre- 

 arum. A more critical examination has shown that it is often found in 

 great numbers in the stomach, especially at its hinder extremity, in 

 which a singularly transparent rod is embedded. In this place they 

 are sometimes found in vast numbers. They do not seem to be a true 

 parasite, but are rather to be regarded as a messmate inhabiting the 

 alimentary tract of the oyster. They are very minute, thread-like 

 organisms, which are provided with an extremely delicate, narrow frill 

 or membrane, which is wound spirally around the body of the animal. 

 The living creature moves rapidly across the field of the microscope, 

 looking very much like a minute animated spiral spring, rotating with 

 a screw-like motion through the liquids taken from the stomach and 

 gut of the oyster. This creature has been encountered by the author 

 in the contents of the stomachs of oysters in Washington and Phila- 

 delphia; also at different places on the shores of the Chesapeake and 

 Chincoteague Bays, and even as far north as Buzzard's Bay. It there- 

 fore seems to be a constant inhabitant of the oyster. It has also been 

 found in other portions of Europe besides the place where it was origi- 

 nally found by M. Certes, who first noticed it in oysters taken from the 

 vicinity of Marennes. This gentleman, in a letter to the writer, dated 

 August 7, says that Professor Motrins has also found it in the oysters of 

 the North Sea. The animal found in the American oyster is apparently 

 very similar if not identical with that found in the fiat oyster (Ostrea 

 edulis) of Europe. 



