28 b CHARACE.E. [Algaw. 



joint of which is born a thread-like antherozoid, rolled up several times upon itself. 

 When these tubes are young their joints contain only a small granular mass — a sort 

 of nucleus — of an oval form and greyish colour ; at the base of the tubes the nuclei 

 are less regular in form ; they have also a higher refractive power, and their edges are 

 better defined. At a later period the nuclei disappear, and on each side of the joint 

 a brilliant point arises, encircled with black, the first indication of the appearance of 

 an antherozoid, and produced by the circumvolution of their thread-like body. By 

 degrees these brilliant points become more numerous ; the outline of the antherozoids 

 becomes more distinct, and the numerous transverse lines which they form on the 

 v>alls of the tube render it impossible to distinguish the partitions. The formation 

 of antherozoids appears to begin always at the upper end of the tubes. By degrees 

 the antherid dehisces ; the valves turn back on the branch of the Chara, dragging 

 with them the oblong vesicle fixed to their centre ; to the extremity of the vesicle 

 adheres a portion of the cellular mass, on which are seated the tubes filled with 

 antherozoids : strange is the appearance then observed with the microscope. The 

 antherozoids are seen twisting and turning all ways in the cavities which enclose 

 them. Eventually they escape by a sudden movement resembling the action of a 

 spring. When free the antherozoid resembles a thread twisted like a corkscrew, with 

 three or four turns, exactly like fragments of spiral vessels. The field of the micro- 

 scope is quickly covered by these little thread-like bodies, swimming with a singular 

 tremulous motion. They turn upon their axis, always preserving the screw form, 

 for their spire seems to have some stiffness, and their motions are caused by the 

 continual agitation of two very long cilia?, of excessive fineness, which spring from a 

 little behind the anterior extremity of the spire on which they seem to fold themselves. 

 The posterior extremity, that is to say, the one which is dragged along by the 

 progression of the antherozoid, is rather granular, thicker, and less neatly defined 

 than the rest of the body. When the activity of the ciliae diminishes, it is easy to see 

 the motion originate at their base and extend by waves in the direction of their 

 length. Iodine, alcohol, ammonia and acids stop their movements. The ciliae resist 

 the action of ammonia longer than the rest of the antherozoid. 



M. Thuret considers the antherozoids of Charas to be unquestionably of the same 

 nature as those of mosses, and he believes that their function is that of impregnation, 

 especially since the spore-cases appear to be constructed for that purpose ; for the 

 latter are surmounted by five cells, which foraa a kind of stigmatic coronet, and when 

 the spore-case is young the cells surround a small canal which, at a later period, disap- 

 pears, as soon as the reproductive body has arrived at a certain stage of growth. 



