1042 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



Source and habitat: Tliaxter (1892, 

 loc. czf.), on various decaying substances, 

 lichens, paper, dung, etc. Smith {loc. 

 cit.), on rabbit dung from Wales. Baur 

 {loc. cit.), on cow and dog dung. De 

 Kruyff {loc. cit.), on stable manure in 

 Java. Jahn (1924, loc. cit.), very com- 

 mon, on almost all specimens of dung, 

 also on bark, decaying wood, and lichens. 

 Krzemieniewski (1927, loc. cit.) very 

 common in Polish soil. Kofler {loc. cit.), 

 dung of rabbit, horse, goat, mouse, roe, 

 deer, on stem of clematis and decaying 

 leaves and in bird nest. 



Illustrations: Cohn {loc. cit.) PI. 

 6, Fig. 18. Smith {loc. cit.) Fig. 1. 

 Baur {loc. cit.) Figs. 1, 2, 3, and PI. 4, 

 Figs. 1-13, 16. Jahn (1924, loc. cit.) 

 Figs. Lr-M, p. 43, Fig. R, p. 47. Krze- 

 mieniewski, Acta Soc. Bot. Poloniae, 4, 

 1926, PI. I, Figs. 7-8. Kofler, Sitzber. 

 d. Kais. Akad. Wiss. Wien. Math. -Nat. 

 Klasse, 122 Abt., 1913, 845, PI. 2, Figs. 

 10 and 12. 



Cultures: Baur {loc. cit.) states that 

 he deposited a pure culture in the Zen- 

 tralstelle fiir Pilzkulturen. 



2. Myxococcus cruentus Thaxter. 

 (Thaxter, Bot. Gaz., 23, 1897, 395; 

 Chondrococcus cruentus Krzemieniewski, 

 Acta Soc. Bot. Poloniae, 5, 1927, 79.) 



Etymology: Latin cruentus, blood-red. 



Swarm stage (pseudo Plasmodium) : 

 Rods 0.8 by 3 to 8 microns. Was not 

 cultivated. 



Fruiting body : Cysts regularly spheri- 

 cal, 90 to 125 microns, blood-red. Slime 

 forms on the surface a more or less defi- 

 nite membrane, in which the spores 

 lie. Spores oval or irregularly oblong 

 about 0.9 to 1 by 1.2 to 1.4 microns. 

 Cysts are densely aggregated. 



Source and habitat : Thaxter {loc. cit.), 

 on cow dung, Tennessee. Krzemieniew- 

 ski (1927, loc. cit.) rare in Polish soils. 



Illustrations : Thaxter {loc. cit.) PI. 31, 

 Figs. 28-29. 



3. Myxococcus virescens Thaxter. 

 (Bot. Gaz., 17, 1892, 404.) 



Etymology : Latin virescens, becoming 

 green. 



Swarm stage (pseudo Plasmodium) : 

 Rod masses greenish-yellow. Rods slen- 

 der, irregularly curved, 0.4 by 3 to 7 

 microns. When cultivated in potato 

 agar tends to lose its green color and 

 becomes yellowish. Badian (1930) re- 

 ports the presence of a dumb-bell -shaped 

 nuclear structure which splits longi- 

 tudinally in cell division, and shows 

 autogamy preceding and a reduction 

 division during spore formation. 



Fruiting body: Spherical or conical, 

 usually less rounded than other species 

 of the genus, yellowish, occasionally 

 greenish, in culture on artificial media, 

 easily becoming white, 150 to 500 microns. 

 The slime deliquesces in continued 

 moisture. Spores large, about 2 microns. 



Source and habitat : Thaxter {loc. cit.), 

 on hen's and dog's dung. New England. 

 Jahn (1924, loc. cit.), not very abundant 

 on dung of rabbit, horse, stag and black 

 cock. Krzemieniewski (1927, loc. cit.), 

 common in soil in Poland. Badian {loc. 

 cit.), Poland. 



Illustrations : Krzemieniewski, Acta 

 Soc. Bot. Poloniae, 4, 1926, PI. I, Fig. 9. 

 Badian, Acta Soc. Bot. Poloniae, 7, 1930, 

 55, PI. 1,8 figures. 



4. Myxococcus xanthus Beebe. (Jour. 

 Bad., 4-^, 1941, 193.) 



Etymology: Greek xanthos, orange, 

 golden. 



Fruiting body : Spherical to subspheri- 

 cal, usually sessile but occasionally con- 

 stricted at the base giving the appearance 

 of a short stalk or foot. Mature fruiting 

 body up to 300 to 400 microns in diameter, 

 often slightly flattened on top or one side. 

 Color varies from light yellowish-orange 

 when young to bright orange when ma- 

 ture; color constant, never tending toward 

 greenish-yellow. No outer cyst wall or 



