86 CHAKACEJE. 



intermingling and anastomosing of the currents described by 

 Mr. Varley." 



This membrane, which must be of exceeding tenuity, is, 

 however, in unhealthy states of the plant no doubt wanting. 

 In certain states of Char a, several large spherical masses 

 are noticed in the central fluid : these are supposed to consist 

 of portions of the innermost dense circulating fluid which 

 have become detached ; and it is by means of these that the 

 absence of the membrane can be demonstrated. The thick 

 circulating fluid does not seem to be visibly affected by 

 gravity, for it follows its usual course in whatever position 

 the cell may be placed : the spherical bodies, which are de- 

 scribed by both Mr. Varley and Mr. Slack, are, however, 

 sensibly affected by gravity : if the cell be placed horizontally 

 and one of these bodies be in the superior current, it will de- 

 scend, slackening its speed as it enters the middle fluid, revolv- 

 ing as it passes through it, and returning by the lower cur- 

 rents : then again, if the plant be reversed, the same globules 

 will again descend, and enter the former stream. The passage 

 of globules from current to current through the central fluid 

 proves that there is now no membrane surrounding it, and 

 also that the central fluid is lighter than the circulating. 

 Fig. 11. represents a cell containing several of these balls or 

 globules. 



For the purpose of tracing and following the course of 

 these globules an apparatus, similar to Mr. Yarley's vial 

 microscope, is necessary. Having now completed the con- 

 sideration of the circulation in the Characea, it remains 

 to treat of the reproduction of the order a subject always 

 of the highest interest in productions belonging to the fresh- 

 water division of the AlgcB. 



We will first describe the organs as they occur in Chara 

 vulgarisj and which will serve as the type of the whole order. 



The branches which compose each whorl in Chara vulgaris 

 are usually nine in number, and consist of four or five cells, 

 the lower ones of which are surrounded by nine other smaller 

 cells, which pursue, like those covering the cells of the stems, a 

 spiral course. At the junction of the major cells with each other. 



