Selenomonad
（重定向自Selenomonas）
![Large forms of Selenomonas from enriched sheep rumen liquor after aldehyde fixation. Phase contrast 100x oil imm., electronic flash. Shows coiled-up flagella and dark linear region along concave side at flagella attachment region.](/Images/godic/202502/10/Seleno_LM4327.jpg")
![Sketch of a sagittal longitudinal ultrathin section through an unidentified large selenomonad from sheep rumen liquor (which seems to correspond closely to descriptions of S. palpitans).](/Images/godic/202502/10/Selenomonad_sls4327.png")
The genus Selenomonas constitutes a group of motile crescent-shaped bacteria within the Veillonellaceae family and includes species living in the gastrointestinal tracts of animals, in particular the Ruminants. A number of smaller forms discovered with the light microscope are now in culture but many, especially the large selenomonads are not, owing to their fastidious and incompletely known growth requirements.