GENERAL SYSTEMATIC BACTERIOLOGY 281 



«ntsprechende Familie der Chaviaesiphonaceae, welche friiher (noch von Raben- 

 horst) zu den Oscillariaceen, den Parallelformen der Leptothricheen gezahlt 

 wurde, von diesen getrennt werden. 



One genus only is included, Crenothrix Cohn. 



Crenothrix. A genus of filamentous bacteria proposed by Cohn 

 (1872, p. 130) for the species Crenothrix polyspora Cohn. Cohn gives 

 the following description: 



Trichomata plus minus stricta arcuata vel contorta in caespitulos libere natan- 

 tes intricata libera vel alia aliis affixa, in modum Oscillariarum cylindrica elon- 

 gate filiformia basi tenuissima sursum paullatim incrassata subulata vel sub- 

 clavata divisione transversa succedanea articulata vaginata hyalina, cellularum 

 plasmate homogeneo intus saepe cavo non granuloso, vagina tenerrima hyalina 

 demum indurata nee non ferro interssuscepto flava. 



Sporangia terminalia apice trichomatum vagina intumescente elongato-clavi- 

 formia gonidiis subglobosis numerosissimis densissime repleta; gonidia duplicis 

 generis, saepissime in fills diversis formata: 



1. Microgonidia e serie cellularum divisione longitudinal! et transversa suc- 

 cedanea multi-partitarum orta, rotundata et diaphragmatibus ruptis im sporan- 

 gium terminale densissime congesta, demum ex apice vaginae erumpentia, in 

 aqua motu lento circumvoluta secedentia vel in cumulos gelatinosos zoogloeis 

 consimiles coacervata, cilii, destituta globosa ovalia elliptica transverse plus- 

 minus constricta vel divisa, demum in trichomata evoluta. 



2. Macrogonidia, singula e cellulae contento toto indiviso, vel bivel quadri 

 partito orta rotundata, ex apice vaginae vix inflatae erumpentia secedentia, motu 

 forma microgonidiis similis sed majora et minus numerosa, demum germinantia. 

 Sporaes? ex articulo trichomatis terminali elongata aucto formata plasmate 

 denso repleta, quod e vagina erumpere et in trichoma Oscillariae forme evolvi 

 videtur. 



Genus unter Lyngbyam et Chamaesiphonem intermedium nee von ad Bangias 

 accedens Oscillarieas cum Florideis connectit. 



The genus was included by Trevisan (1879, p. 138) in his subtribe 

 Euvibrionieae with the following description: 



Somatia cylindrica distincte articulata, valida, elongata, arcuata vel contorta, 

 in caespitulos intricata, microgonidia e serie cellularum divisione longitudinali et 

 transversa succedanea multipartitarum orta, globulosa, diaphragmatibus ruptis 

 in pseudosporangium terminale densissime congesta, demum ex apice vaginae 

 erumpentia et in somatia evoluta, foventia. 



The genus has been generally recognized by subsequent writers. 

 Winter (1880) and Grove (1884, p. 54) used the following definition: 



Threads cylindrical, somewhat clavately thickened upwards, articulated, 

 provided with a sheath. Multiplication by means of the joints, which escape 



