260 



ORDER I. PSEUDOMONADALES 



at the middle of the concavity. The so-called 

 nuclear body shows plainly in the electron 

 micrographs. 



Source: Isolated from the buccal cavity of 

 man. 



Habitat: Found in the buccal cavity. 



3. Selenoinonas runiinantium (Certes, 

 1889) Wenyon, 1926. {Ancyromonas runiinan- 

 tium Certes, Bull. Soc. Zool., France, H, 

 1889, 70; Selenomastix ruminantium Wood- 

 cock and Lapage, Quart. Jour. Micro. Sci., 

 59 (N.S.), 1913-1914, 433; Wenyon, Proto- 

 zoology. 1, 1926,311.) 



ru.mi.nan'ti.um. L. part. adj. ruminans, 

 ruminantis ruminating; M.L. neut.pl.n. 

 ruminantia ruminants; M.L. pi. gen. noun 

 ruminantium of ruminants. 



Rigid, crescent-shaped cells which meas- 

 ure 2 to 3 by 9.5 to 11 microns. Woodcock and 

 Lapage {op. cit., 434) state that the cells are 

 only slightly crescentic and never assume 

 the S shape as reported by Certes (op. cit., 

 439); furthermore, they report that the 

 curve lies in but one plane. A tuft of flagella 

 which attains a length of 8.0 to 9.5 microns 

 springs from the center of the concavity. 

 The protoplasm stains homogeneously ex- 

 cept at the base of the flagella where a 



deepl}^ staining mass is easily demonstrable. 

 Reproduction is by binary fission transverse 

 to the long axis of the cell and through the 

 flagellar region. Each half of the flagella 

 passes to one of the two pear-shaped daugh- 

 ter cells where it is attached near the blunt 

 end; later the flagella undergo an apparent 

 shift in position to the center of the con- 

 cavity. 



Probably anaerobic but does not grow on 

 ordinary media either aerobically or an- 

 aerobically. 



Woodcock and Lapage (op. cit., 445 ff.) 

 found ellipsoidal, non-motile organisms 

 mixed abundantly with the motile crescents 

 and felt that these might represent a stage in 

 the life history of the crescents although 

 they could not demonstrate this. Wenyon 

 {op. cit., 311) also thinks that a rounded 

 flagellate organism may be a stage of the 

 crescent-shaped organism, but he presents 

 no proof to support this conclusion. 



Source: Found by Certes {op. cit., 70) by 

 microscopical examination of rumen juice 

 of cattle, sheep and deer. Later found by 

 Woodcock and Lapage {op. cit., 433) very 

 abundantly in the rumen juice of goats. 



Habitat : Found as a predominant organ- 

 ism on microscopical examination of rumen 

 juices from herbivorous mammals. 



Genus X. Myconostoc Cohn, 1875.* 

 (Beitrage z. Biol. d. Pflanzen, 1, Heft 3, 1875, 183.) 



My.co.nos'toc. Gr. noun myces fungus; M.L. neut.n. Nostoc a genus of algae; i\LL. neut.n. 

 Myconostoc fungus nostoc. 



Curved, colorless cells occurring singly or in curved or spiral chains. Embedded in small, 

 spherical, gelatinous masses. Found in fresh- or sulfur-water containing decomoosine 

 organic matter. 



The type species is Myconostoc gregarium Cohn. 



1. Myconostoc gregarium Cohn, 1875. 

 (Cohn, Beitrage z. Biol. d. Pflanzen, 1, 

 Heft 3, 1875,_ 183; Spirosoma gregarium 

 Migula, Syst. d. Bakt., ^, 1900, 960.) 



gre.gar'i.um. L. adj. gregarius of or be- 

 longing to a flock or group. 



Cells curved to comma-shaped, 1 by 5 to 

 10 microns, often joined together as spiral 

 chains which may resemble horse-shoes or 

 which may twist around each other to form 



coiled, non-septate, non-motile, colorless 

 filaments. The filaments are usually en- 

 closed in a spherical, solid, microscopic, 

 gelatinous mass which measures 10 to 17 

 microns in diameter; these masses may 

 clump together and form a cluster, usually 

 on the surface of the water, which is visible 

 to the naked eye. Excellent illustrations de- 

 picting the nature of this species are shown 

 in Zopf (Die Spaltpilze, 3 Aufl., 1885, 23). 



* Prepared by Mr. Erwin F. Lessel, Jr., Cornell University, Ithaca, New York. Septem- 

 ber, 1953. 



