59. Selenomonas 



The genus Seleno7nonm apparently has a ubiquitous distribu- 

 tion in nature. It appears to be a common inhabitant of the cow 

 rumen, the human throat, dog intestine, river water, etc. It is 

 anaerobic and somewhat fastidious in its growth requirements. 

 Morphologically it is unique, with a slight curvature to the soma 

 and unusual flagellar arrangement (Fig. 66). 



One culture labeled Selenomonas ruminantium was received 

 from Marvin Bryant of the U.S.D.A. It was isolated from cow 

 rumen. Similar appearing organisms were seen by the author in 

 material from dog intestine and in river water but these were not 

 isolated. A culture labeled Spirillum spiitigenum was received 

 from J. B. Macdonald of Harvard University. Growth of this 

 organism was rather unsatisfactory but sufficient organisms were 

 present for staining. 



Fig. 66. a, b, c. Selenomonas ruminantium, Bryant. These are typical ex- 

 amples of single individuals. The soma is slightly curved and the flagella orig- 

 inate as a tuft from the concave side. 



d, 6. S. ruminantium, Bryant. These organisms appear to be in the process 

 of cell division. In d the left half is starting to develop flagella. In e each 

 half has a distinct tuft of flagella. 



f. S. ruminantium, Bryant. This organism appears to have been turned 

 so the concave side is up. The flagella appear to orignate from a disklike 

 structure. 



g. S. ruminantium, Bryant. This individual shows a single \ariant flagellum, 

 which might be labeled curly, in addition to the normal flagella. This was 

 the only flagellar variant observed in all the slides examined. The wavelength 

 of this curly flagellum is 1.2 microns. 



h. S. ruminantium, Bryant. The several flagella which can be seen emanat- 

 ing from the soma are twisted into a single strand. 



i. S. ruminantium, Bryant. Flagella of two organisms twisted together. 

 What else could it be? 



j. Selenomonas sp. Organism stained directly from water of the DuPage 

 River in Illinois. 



k. Selenomonas sp. Organism stained directly from the intestinal content 

 of a dog. Note the smaller somatic size of this organism compared to S. rumi- 

 nantium and the strain from the DuPage river. 



1. Spirillum (Selenomonas) sputigenum, Macdonald. The flagellar ar- 

 rangement and wavelength classifies this organism as Selenomonas. The 

 soma is smaller than that of S. ruminantium and comparable to that of the 

 organism from the dog intestine. 



154 



