44 ELEMENTARY BIOLOGY. [VI. 



primordial utricle, in which the nucleus is imbedded. In 

 the larger cells the primordial utricle is readily detached 

 and made to shrivel up into the middle of the cell by 

 treatment with strong alcohol. 



Numerous small green bodies chlorophyll grains are 

 imbedded in the outer, or superficial, part of the primordial 

 utricle. And they increase in number by division, as the cell 

 enlarges. These chlorophyll grains are composed of proto- 

 plasmic matter, which frequently contains starch granules, 

 and is impregnated with the green colouring substance. 



During life, the layer of the primordial utricle which 

 lies next to the watery contents of all the larger cells is 

 in a state of incessant rotatory motion, while the outermost 

 layer which contains the chlorophyll grains is quite still. In 

 the large cells, so long as the nucleus is discernible, it is 

 carried round with the rotating stream. 



The antheridium is a globular spheroidal body with a 

 thick wall, made up of eight pieces, which are united by 

 interlocking edges. The four pieces which make up the hemi- 

 sphere to which the stalk of the antheridium is attached, are 

 foursided, the other four are triangular. From the centre of 

 the inner, concave face of each piece a sort of short process, 

 the handle or manubrium, projects into the cavity of the 

 hollow sphere. At the free end of the manubrium is a 

 rounded body, the capitulum, which bears six smaller, second- 

 ary capitula ; and each secondary capitulum gives attachment 

 to four long filaments divided by transverse partitions into 

 a multitude (100 to 200) of small chambers. Thus, there 

 may be as many as 20,000 to 40,000 chambers in each 

 antheridium (8 x 6 x 4 x 100 or x 200). The several pieces of 

 which the wall of the antheridium is composed, the manubrium, 

 the capitula, the secondary capitula and the chambers of the 

 filaments, are all more or less modified cells, as may be proved 

 by tracing the antheridia from their earliest condition, as 



