154 HOFMEISTER, ON 



which immediately encloses the contents of the epidermal 

 cells, is filled with a transparent, almost fluid, jelly, which 

 can be nothing else than a product of the swelling up of 

 the median layer of the walls of those cells which occupy 

 the apex of the antheridium. Suddenly the cuticle of both 

 the above-mentioned cells splits transversely ; the contents 

 of the antheridium are driven out between the detached 

 cells of the epidermal layer in the form of a mucilaginous 

 mass, shaped like intestines ; these contents escape at first 

 with great rapidity, and afterwards with a slower motion, 

 which sometimes, by fits and starts, exhibits a momentary 

 acceleration. The walls of the cellules in which the len- 

 ticular vesicles, which produce the spermatoza, are gener- 

 ated, are now swollen to a mucilaginous jelly. The latter 

 is rapidly dissolved in water on the stage of the microscope, 

 the vesicles are dispersed in the fluid, and are soon rup- 

 tured by the spermatozoa in their efforts to escape. The 

 latter move about for some little time in the water, but 

 with no very great rapidity. I have observed the motion 

 to last for four hours in Polytrichimformosum. The mode 

 of bursting of the antheridium leads to the conclusion that 

 a radial expansion, and swelling up of the walls of the 

 epidermal cells, especially of those of the apex, are at least 

 as effective in producing the rupture, as is the outward 

 pressure produced by the swelling of the contents. 



The development of the antheridia of Sphagnum, which 

 are situated singly in the axils of short lateral shoots, differs 

 in some points of secondary importance from that which 

 occurs in Phascum, Bryum, Funaria, &c. There is a long 

 row of cells of the second degree in which division does not 

 take place ; a thin cylindrical double row of cells is pro- 

 duced, the end of which swells in a clavate manner. A 

 few only (two or three) of the cells belonging to the double 

 pairs of cells of the third degree which lie nearest to 

 the apex of the organ, divide, by means of a septum 

 parallel to the outer surface, into inner and outer cells 

 (PI. XVIII, fig. 11). The former become the mother- 

 cells of the vesicles which produce the spermatozoa ; they 

 divide actively in all three directions until at last they form 

 a spherical or oval group of closely-packed, small, tessellated 



