1018 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



Etymology: Greek gephyra, a bridge. 

 So named because a transition form 

 between the Archangiaceae and the 

 Myxococcaceae. 



Swarm stage (pseudo Plasmodium): 

 Grows easily in manure decoction, 

 forming a pseudoplasmodium and ring of 

 fruiting bodies. The vegetative rods 

 are about 10 microns long, 0.5 micron in 

 diameter. 



Fruiting bodies: Up to 1 mm in di- 

 ameter, of irregular form and with 

 swollen or padded surface. Average 

 sized fruiting bodies are a reddish flesh 

 color by reflected light; smaller fruiting 

 bodies, a light rose. On a dark back- 

 ground large fruiting bodies when fresh 

 appear bluish violet. By transmitted 

 light the fruiting bodies appear yellowish 

 to light red. Upon addition of alcohol or 

 when heated in glycerine, they lose the 

 color quickly and appear gray or 

 colorless. 



The inner structures are for the most 

 part a mesenteric mass of tubes 40 to 60 

 microns wide, without any membrane, 

 and without any enclosing slime. The 

 convolutions are often pressed together. 

 On the inside of these tubes there appears 

 definitely a septation by straight or 

 slightly arched cross walls which, how- 

 ever, do not always cut entirely through 

 the spore masses from one side of the tube 

 to the other. Upon pressure, the fruiting 

 body breaks up into a number of small 

 fragments about 15 to 30 microns in 

 diameter. Within these fragments the 

 shortened rods lie parallel and in bundles. 



The rods in the fruiting bodies are so 

 shortened that they resemble the spores 

 of the Myxococcaceae. The spores are 

 2.5 to 2.8 microns long and about 1.4 

 microns wide. Often they are somewhat 

 bent so that they appear to be bean- 

 shaped. In the smooth, transparent tips 

 of fruiting bodies they stand closely 

 parallel to each other, so that in trans- 

 mitted light one sees only their cross 

 section and is at first led to believe that 



he is dealing with one of the Myxo- 

 coccaceae. 



Source and habitat : Found frequently 

 in the region of Berlin on the dung of 

 deer, rabbits, and hare, once also on old 

 decaying lichens. Easily overlooked on 

 account of its usual bluish color. Accord- 

 ing to Krzemieniewski (1927) the most 

 common of myxobacteria in the soils of 

 Poland. Isolated on rabbit dung. 



Illustrations: Quehl {loc. cit.) PI. 1, 

 Fig. 7. Jahn (1924, loc. cit.) PI. 1, Fig. 5. 

 Krzemieniewski, Acta Soc. Bot. Polo- 

 niae, 4, 1926, PI. Ill, Figs. 25-26. 



2. ArChangium primigenium (Quehl) 

 Jahn. {Polyangiurn primigenium Quehl, 

 Cent. f. Bakt., II Abt., 16, 1906, 16; 

 Jahn, Beitrage zur botanischen Pro- 

 tistologie. I. Die Polyangiden, Geb. 

 Borntraeger, Leipzig, 1924.) 



Etymology : Latin, primigenius, primi- 

 tive, referring to the simple and primitive 

 character of the fruiting body. 



Swarm stage (pseudoplasmodium) : In 

 manure decoction cysts germinate readily. 

 Vegetative rods 4 to 8 microns in length. 



Fruiting bodies : Up to 1 mm in di- 

 ameter, sometimes larger, with irregu- 

 larly padded swollen surface; when 

 fresh a lively red color which is quite 

 prominent especially against a dark back- 

 ground; when dried, dark red. In 

 transmitted light flesh red to yellowish 

 red. In alcohol and upon heating it is 

 quickly bleached. 



In transmitted light one sees that the 

 fruiting body is made up of numerous 

 intestine-like convolutions closely ap- 

 pressed, not however, always definitely 

 delimited. These tubes usually have a 

 diameter of from 70 to 90 microns, often 

 constricted and attenuated. No mem- 

 brane is present. The rods in the fruit- 

 ing bodies are about 4 microns long and 

 0.8 micron wide. Upon pressure on the 

 fruiting bodies, the rods remain together 

 in small fragments of various sizes. 



2a. Archangium primigenium var. 



