1048 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



Etymology: Greek diskos, a quoit, dis- 

 cus; Latin formis, shape. 



Swarm stage (pseudoplasmodium ) : 

 Rods 0.5 to 0.6 by 2 to 3 microns. 



Fruiting bodies: Cysts disk-shaped, 

 crowded, sessile, attached by a more or 

 less ragged scar-like insertion, or in 

 masses. Cysts yellowish when young, 

 when old dark orange-yellow, about 35 by 

 10 microns. Cyst wall distinct, thin, be- 

 coming very slightly wrinkled. Spores 

 irregularly spherical, embedded in vis- 

 cous slime, difficult to see in the ripe cyst. 



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

 dung of muskrat and deer, Massachusetts 

 and New Hampshire. Krzemieniewski 

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



Illustrations : Thaxter (loc. cit.) PI. 27, 

 Figs. 19-21. Krzemieniewski Acta Soc. 

 Bot. Poloniae, 4, 1926, PI. II, Figs. 

 21-22. 



2. Angiococcus cellulosum Mishustin. 



(Microbiology, Moscow, 7, 1938, 427.) 



Etymology: Modern Latin cellulosum, 

 cellulose. 



Fruiting body : Regularly rounded (less 

 frequently extended or angular), 20 to 

 150 microns in diameter; yellow or pink 

 in color, to drabbish when old. Encysted 

 cells surrounded by a colorless cyst wall 



or envelope. Usually 1 to 3 short stalks 

 or cystophores up to 10 microns high. 

 Within outer wall are numerous cysts 

 containing resting cells (spores). Cysts 

 have regularly rounded form; unpig- 

 mented to yellow; 5 to 15 microns in 

 diameter, average 6 microns. Number 

 of cysts ill fruiting body increases with 

 age. 



Spores : Cocci (term used is shortened 

 rods) combined into globular aggrega- 

 tions easily broken up. Size not given. 



Vegetative cells: 0.4 to 0.5 by 1.5 to 

 2.0 microns. Cell contents pigmented 

 gray, and of indefinite outline (?). 



Vegetative colony : Fairly rapid growth 

 on cellulose with silica gel . Colony has a 

 yellowish cast. Reaches diameter of 

 1.5 to 2.0 cm after 6 days with center 

 yellowish-pink and margin tinged light 

 pink. Surface moist. Fruiting bodies 

 more numerous at center, but distributed 

 over entire area. Fruiting bodies do not 

 noticeably protrude above the surface 

 of the colony. 



Physiology : Cellulose attacked but not 

 completely destroyed. Lower fibers re- 

 main intact, but on treatment with hot 

 soda solution they fall spart. 



Habitat : Soils. 



Genus IV. Sporocytophaga Stanier. 



(Jour. Bact., 40, 1940, 629.) 



Diagnosis : Spherical or ellipsoidal microcysts formed loosely in masses of slime 

 among the vegetative cells. Fruiting bodies absent. 



Etymology: Greek sporos seed, spore; kytos hollow place, cell and phagein to eat. 

 The type species is Sporocytophaga myxococcoides (Krzemieniewska) Stanier. 



Key to the species of genus Sporocytophaga. 



I. Microcysts spherical. 



A. Does not utilize starch. 



B. Utilizes starch. 

 II. Microcysts ellipsoidal. 



1. Sporocytophaga myxococcoides. 



2. Sporocytophaga congregata. 



3. Sporocytophaga ellipsospora. 



