Similar in morphology to Simonsiella muelleri but broader. Habitat: Found on the mucous mem- branes of the oral cavities of domestic ani- mals. 3. Simonsiella filiforinis Schmid, 1922. (Schmid, in Simons, Cent. f. Bakt., I Abt., Orig., 88, 1922, 509.) fi.li.for'mis. L. noun filum thread; L. noun forma shape; M.L. adj. filiformis fili- form. Cells occur in long, pointed chains which vary in width at several places along their lengths. Habitat: Found in mucus from the oral cavities of domestic animals. FAMILY II. OSCILLOSPIRACEAE PESHKOFF, 1940. (Jour. Gen. Biol. (Russian), 1, 1940, 611 and 616.) Os.cil.lo.spi.ra'ce.ae. M.L. neut.n. Oscillospira type genus of the family; -aceae ending to denote a family; M.L. fem.pl.n. Oscillospiraceae the Oscillospira family. Cells occur in trichomes of varjdng lengths. The trichomes are partitioned to form narrow cells, each containing a central chromatin body (disc-like nucleus); these bodies give a clear Feulgen reaction and are embedded in hyaline protoplasm. Spores are formed by a fusion of the protoplasms of two to three neighboring cells. Actively motile by means of peritrichous flagella; non-motile strains may occur. Parasitic in the intestinal tracts of ver- tebrates. There is a single genus, Oscillospira. Genus I. Oscillospira Chatton and Perard, 1913. (Chatton and Perard, Compt. rend. Soc. Biol., Paris, 65, 1913, 1159; also see Pringsheim, Bact. Rev., 13, 1949, 75 and 76.) Os.cil.lo.spi'ra. L. neut.n. oscillum a swing; Or. noun spira a spiral; M.L. fem.n. Oscil- lospira the oscillating spiral. These bacteria occur as trichomes of varying lengths which contain a limited number of discoid cells which are usually biconcave and end cells which are approximately hemispher- ical. Cell division is by a diaphragm-like ingrowth of the trichome wall. Spores, usually one, rarely two, are formed which resemble endospores; they are too large to be accommo- dated by a single cell, and therefore several cells in a trichome break down to form a spore chamber. Motile by means of peritrichous flagella, although non-motile strains may occur. Anaerobic or, more probably, microaerophilic. Found in the alimentary tracts of animals, especially in the rumina of ruminants and the caeca of guinea pigs. The type species is Oscillospira guilliermondii Chatton and P6rard. 1. Oscillospira guilliermondii Chatton and Perard, 1913. (Compt. rend. Soc. Biol., Paris, 65, 1913, 1159.) guil.lier.mon'di.i. M.L. gen. noun guil- liermondii of Guilliermond; named for Prof. A. Guilliermond, a French biologist. Sturdy trichomes with a diameter of 5 nucrons and a length which never exceeds 100 microns. The extremities are rounded with approximately hemispherical end- cells. The biconcave, discoid cells within the trichomes are 1 to 2 microns long and homogeneous or finely granular in appear- ance. Spores, which average 2.5 by 4.0 mi- crons, are ellipsoidal and are oriented lengthwise on the long axis of the trichome or are very slightly inclined on this axis. Because the spore chamber is formed by the breakdown of several cells, it is con- siderably longer and slightly wider than the remaining cells. Sporulating trichomes, which contain one, rarely two spores, are infrequently found; the spores are located
