68 PRINGSHEIM, ON THE IMPREGNATION 



mucous substance, of whose constitution, however, no clear 

 insight can be obtained. Now, so soon as the transformation 

 of the contents has taken place, the apex of the hornlet, so 

 far as it is colourless, is suddenly parted from the lower, 

 green portion by a septum, and is thus transformed into an 

 independent cell, having no communication with the parent 

 tube, and the basal part of the hornlet. In this case the 

 septum is not formed as in the sporangium, at the base of 

 the process, but in the middle. But the point at which the 

 septum is formed, in the " hornlet," is not very determinate ; 

 the portion thus cut off from the rest being sometimes larger 

 sometimes smaller. 



After the formation of the septum in the " hornlet," the 

 colourless mucus in its apex gradually assumes a more deter- 

 minate form, and at this time a large number of minute, 

 perfectly colourless, rod-like bodies may be readily perceived 

 crowded together irregularly, and which being still here and 

 tliere surrounded by the amorphous mucus are, as it were, 

 imbedded in it. Close observation also will disclose an in- 

 distinct movement exhibited even thus early by some of 

 the little rods, and from which their destination may be 

 anticipated. 



This perfecting of the " hornlet " coincides in time with 

 that stage of development of the sporangium, at which the 

 accumulation of the " cutaneous layer" in the anterior part of 

 the rostrate process has attained to its greatest extent ; and 

 this condition of the sporangium and of the hornlet immediately 

 precedes the act of impregnation. 



This is effected in the following manner : the pressure 

 within the sporangium upon its walls, and especially in the 

 direction of the rostrum, becomes greater and greater in con- 

 sequence of the continued increase of the " cutaneous layer " 

 in the forepart of the rostrum, until ultimately the membrane 

 is ruptured exactly at the point of the rostrum, and allows a 

 portion of the " cutaneous layer" to escape (fig. 6). The de- 

 tachment of the extruded portion is attended with all the 

 appearances which accompany the slow separation of a mucous 

 substance into two portions, and which in the present case 

 show in the clearest manner the non-existence of any mem- 

 brane around the escaped portion of contents. This portion 

 then assumes the character of a drop of mucus, which remains 

 lying near the opening of the sjwrangium, and without under- 

 going any organization perishes, after exhibiting the various 

 phenomena due to the absorption of water and disintegration 

 (figs. 7 and 8). The accumulation of the " cutaneous layer " 

 in the interior of the sporangium^ in the anterior part of the 



