1040 MANUAL OF DETERMINATIVE BACTERIOLOGY 



FAMILY V. MYXOCOCCACEAE JAHN. 



(Beitrage zur botan. Protistologie. I. Die Polyangiden, Geb. Borntraeger, Leipzig, 

 1924, 84.) 



Diagnosis : The rods become shortened when fruiting occurs (resting cells are 

 formed), and develop into spherical or ellipsoidal spores or microcysts. LTpon germi- 

 nation the vegetative cell develops from the spore by a process analogous to budding, 

 pinching off at the point of emergence, leaving the spore wall entirely empty. In three 

 of the genera, definite fruiting bodies are produced. In Sporocytophaga, the spores 

 (microcysts) are produced from the vegetative celjs without development of fruiting 

 bodies. 



Key to the genera of family Myxococcaceae. 



I. Definite fruiting bodies formed. 



A. Fruiting body not containing or made up of cysts. 



1. Fruiting bodies deliquescent. 



Genus 1. Myxococcus, p. 1040. 



2. Fruiting bodies firm, not deliquescent. 



Genus II. Chondrococciis, p. 1044. 



B. Fruiting body made up of cysts. 



Genus III. Angiococcus , p. 1047. 

 II. No definite fruiting bodies formed. 



Genus IV. Sporocytophaga, p. 1048. 



Genus 1. Myxococcus Thaxter. 



(Bot. Gaz., 17, 1892, 403.) 



Etymology: Greek myxa, mucus and kokkos, berry; slime sphere. 

 Diagnosis : Spherical spores in conical or spherical or occasionally ovoid upright 

 fruiting bodies, united by a loose more or less mobile slime. 

 The type species is Myxococcus fulvus (Cohn emend. Schroeter) Jahn. 



Key to the species of genus Myxococcus. 



I. Stalk lacking or indicated only by a constriction. 



A. Spores average less than 1.4 microns in diameter. 



1. Fruiting body red or brownish-flesh color. 



1. Myxococcus fulvus. 



2. Fruiting body light blood-red. 



2. Myxococcus cruentus. 



B. Spores average 2.0 microns in diameter. 



1. Fruiting body yellow to greenish-yellow. 



3. Myxococcus virescens. 



2. Fruiting body yellow -orange to orange. 



4. Myxococcus xanthus. 



II. Well developed stalk supporting spherical spore mass above. 



A. Spores spherical. 



5. Myxococcus stipitalus. 



B. Spores oval. 



6. Myxococcus ovalisporus. 



