884 



ORDER VIII. MYXOBACTERALES 



crons. Jahn {loc. cit.) notes two varieties of 

 this species, one white, the other cinnabar- 

 red. 



Gelatin is quickly liquefied, completely 

 in 1 to 2 days, but no fruiting bodies are 

 formed . 



Kofler secured good growth on Hasting's 

 milk agar and determined digestion of 

 casein. 



Source: Isolated by Thaxter (Bot. Gaz., 

 17, 1892, 403) from various decaying sub- 

 stances such as lichens, paper, dung, etc. 

 Found by Smith (Jour. Bot., 39, 1901, 71) on 

 rabbit dung from Wales, by Baur (Arch. f. 

 Protistenkunde, 5, 1905, 95) on cow and dog 

 dungs, by de Kruyff (Cent. f. Bakt., II Abt., 

 21, 1908, 386) on stable manure in Java, by 

 Jahn {op. cit., 1924, 84) on almost all speci- 

 mens of dung, as well as on bark, decaying 

 wood and lichens, by Krzemieniewski (Acta 

 Soc. Bot. Poloniae, 5, 1927) in Polish soil, 

 and by Kofler (Sitzber. d. kais. Akad. wiss. 

 Wien, math.-nat. Klasse, Abt. I, 122, 1913) 

 on the dung of rabbit, horse, goat, mouse, 

 roe and deer and on the stem of clematis 

 and decaying leaves and in bird nest. 



Habitat: Found on decaying organic mat- 

 ter in soil and in the dung of various ani- 

 mals. 



Illustrations: Cohn {op. cit., 1875, PI. 6, 

 Fig. 18), Smith {op. cit., 1901, Fig. 1), Baur 

 {op. cit., 1905, Figs. 1-3 and PI. 4, Figs. 1-13, 

 16), Jahn {op. cit., 1924, Figs. L-M, page 43; 

 Fig. R, page 47), Krzemieniewski {op. cit., 

 4, 1926, PI. 1, Figs. 7-8) and Kofler {op. cit., 

 1913, 845, PI. 2, Figs. 10 and 12). 



2. Myxococcus cruentus Thaxter, 1897. 

 (Bot. Gaz., 23, 1897, 395.) 



cru.en'tus. L. adj. cruentus blood-red. 



Vegetative cells: Rods 0.8 by 3.0 to 8.0 

 microns. Not cultivated. 



Fruiting body: Regularly spherical, 90 

 to 125 microns, blood-red. Slime forms on 

 the surface a more or less definite membrane 

 in which the microcysts lie. Microcysts el- 

 lipsoidal or irregularly oblong, 0.9 to 1.0 by 

 1.2 to 1.4 microns. 



Source: Isolated from cow dung from Ten- 

 nessee. 



Habitat: Found on decaying organic mat- 

 ter in soil and in the dung of various ani- 

 mals. Krzemieniewski (Acta Soc. Bot. Po- 



loniae, 5, 1927) states that it is rarely found 

 in Polish soils. 



Illustrations: Thaxter {op. cit., 1897, PI. 

 31, Figs. 28-29). 



3. Myxococcus virescens Thaxter, 1892. 

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



vi.res'cens. L. part. adj. virescens becom- 

 ing green. 



Vegetative cells: Rod masses greenish 

 yellow. Rods slender, irregularly curved, 

 0.4 by 3.0 to 7.0 microns. When cultivated 

 on potato agar, they tend to lose their green 

 color and become yellowish. 



Fruiting body: Spherical, usually less 

 rounded than other species of the genus, 

 3'ellowish, occasionally greenish, in culture 

 on artificial media, easily becoming white, 

 150 to 500 microns. The slime deliquesces in 

 continued moisture. Microcysts large, about 

 2 microns. 



Source : Isolated from hen and dog dungs 

 from New England. Jahn (Beitrage zur bot. 

 Protistologie. I, Die Polyangiden. Geb. 

 Borntraeger, Leipzig, 1924) states that it 

 is not very abundant on the dungs of rabbit, 

 horse, stag and black cock. 



Habitat: Found on decaying organic mat- 

 ter in soil and in the dung of various ani- 

 mals. Common in Polish soil, according to 

 Krzemieniewski (Acta Soc. Bot. Poloniae, 

 5, 1927). 



Illustrations: Krzemieniewski {op. cit., 

 4, 1926, PI. 1, Fig. 9) and Badian (Acta Soc. 

 Bot. Poloniae, 7, 1930, 55, PI. 1, 8 Figures). 



4. Myxococcus xanthus Beebe, 1941. 



(Jour. Bact., 4^, 1941, 193.) 



xan'thus. Gr. adj. xanthus orange, golden. 



Vegetative cells: Large, flexible, single, 

 Gram-negative rods with rounded ends. 

 Vary in size from 0.5 to 1.0 by 4.0 to 10.0 

 microns; average, 0.75 by 5.0 microns. 



Fruiting body: Spherical to subspherical, 

 usually sessile but occasionally constricted 

 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 mature; color constant, 

 never tending toward greenish yellow. No 

 outer cyst wall or limiting membrane dis- 



