70 THE JOURNAL OF BOTANY 



has described. This is the second state, and is the resting or en- 

 C3^sted stage of the Myxohacteria ; a gelatinous wall is formed round 

 the cysts, and they are capable of resisting adverse conditions such 

 as cold, drought, or mechanical disturbance. In the simplest types, 

 the resting stage is formed of simple, papillate, upright bodies, 

 sessile or supported on a stalk ; but others have a much more com- 

 plicated appearance, being fashioned into coralloid coiled strands, 

 or into elongate branched stalks with numerous heads. In due 

 time the contents of the cyst, rods or cocci, emerge, and the life- 

 cycle begins over again. The cysts of the Myd'ohacteria are brightly 

 coloured, so far as they have been observed ; they are usually of 

 some shade of yellow or red, but brown and green species have also 

 been noted. Most of them retain their bright colours, with some 

 variations, through the different life-stages. 



Prof. Thaxter distinguishes three groups or genera of Myxo- 

 hacteria — Cliondromyces and My.robacter, in which the encysted and 

 swarming stage are equally composed of rods ; and Myxococcus, in 

 which the rods become transformed into cocci or spores when they 

 form into cysts. In Chondromyres the cysts remain more softly 

 gelatinous, and may fuse togetlier if adjacent to each other. The 

 cysts of Myx'>hacUr have a thick-walled gelatinous envelope, in 

 wliich are included one or more cysts. The first member of the 

 family tliat was recorded was Chontlromyccs crocatus Berk. & Curt., 

 from South Carolina. It has an upright, somewhat branched 

 irreguhir stalk, and several heads. The authors placed it among 

 the Hyphoniycetes, where it remained until rescued by Prof. Thaxter, 

 who has had it under observation, and who has described its true 

 nature and affinities. 



Zukal, in a paper published in the Berich. Deut. Bot. Gesel. 

 vol. XV. p. 542 (1897), states that the old monotypic genus Pdly- 

 angium of Link is the same as Thaxter's genus Myxohacter, and 

 claims for it priority of nomenclature. He had had PuJyangium 

 vitellinum under observation some years ago, and considered it then 

 to be a species of Mycetozoon ; it is to be regretted that Zukal does 

 not give a more detailed account of his observations of Polyanyium. 

 In 1886, Schroter, in Pilze Schl. p. 170, founded the genus Cysto- 

 hacter, with two species. Both of these are typical Myxohacteria, 

 and, in a paper published in the Bot. Gazette, vol. xxiii. p. 395 

 (1897), Prof. Thaxter accepts Cystobacterfidvus Schrot. as a member 

 of his Myxohdcter group, and sinks the name in favour of Schroter's. 

 The other species described by Schroter belongs to the older genus 

 • Cliondromyces. 



In the same paper Prof. Thaxter follows up his previous 

 observations by a further description of spore-formation in Myxo- 

 coccus. The rods in this genus do not divide for sporulation, as he 

 at first thought they did ; they gradually enlarge at one end, and 

 become shorter, each rod forming an almost round spore. The 

 subsequent germination of these spores or cocci was also followed 

 most satisfactorily; their contents formed into a rod which emerged 

 from the spore, the empty case being left behind, or in some cases it 

 remained for a time attached to the end of the full-grown rod. 



