Ward . — Thames Bacteria , III. 
251 
Number 31. 
Fig. 46. Colonies from a six-days’ plate at 18-2 1° C., natural size. 
Fig. 47. Similar colonies under i from a forty-eight hours’ plate : a emerged ; 
b submerged ; c ‘ floating islands ’ more highly magnified. 
Fig. 48. A colony from an eight-days’ plate, natural size. 
Number 17. 
Fig. 49. Plate-colonies of No. 17 at 18-2 1° C., for three days : a natural size ; 
b an emerged colony under ; c submerged colony under 
Fig. 50. The same on the fifth day : a an emerged colony, natural size ; b a part 
of one of its marginal outlyers ; c a submerged colony under 
Fig. 51. A colony twelve days at 20° C., natural size, liquefying. 
Fig. 52. Stab-cultures at 18-21° C. : a on third day ; b on fifth day. 
Fig. 53. Agar-culture one month at 25°C. 
B. arborescens. 
Fig. 54. A typical plate-colony of B. arborescens isolated from the river, two 
days at ordinary temperatures (15-17 0 C.) : a natural size; b under the 
Fig. 55. a A slowly grown plate-colony on sixth day under b another colony 
on sixth day, and c the same on eighth day, both under 
Fig. 56. Quickly grown colony in dark at 20°C., forty-eight hours, under 
In this condition they rapidly liquefy the plate. 
Fig- 57- Colonies retarded by light, four days old : a natural size; b under 
Fig. 58. Stab-cultures at I5°C. : a and b after two days; c fifth day; d three 
weeks. 
Fig. 59. Agar-culture three days at 20° C. 
Fig. 60. Potato-culture seven days at 20° C. 
Fig. 61. Rodlets from gelatine-cultures. 
Fig. 62. Colonies from a seven-days’ gelatine-plate in the dark at low temper- 
atures (6-1 2 0 C.), showing retardation and complete change of form. 
Fig. 63. Plate-colonies of variety (b) as isolated : a natural size ; b the same 
under £ ; c natural size ; d the same under 
