434 ELEMENTARY BIOLOGY. [CHAP. 



brium is a rounded body, the capituluvi, which bears six 

 smaller secondary capitula ; and each secondary capilulum 

 gives attachment to four long filaments divided by trans- 

 verse partitions into a multitude (loo to 200) of small 

 chambers. Thus, there may be as many as 20,000 to 

 40,000 chambers in each autheridium (8x6x4x100 or 

 X 200). The several pieces of which the wall of the an- 

 theridium is composed, the manubria, the capitula, the 

 secondary capitula and the chambers of the filaments arc 

 all more or less modified cells, as may be proved by tracing 

 the antheridia from their earliest condition, as small pro- 

 cesses of the nodal region, to their complete form, 'i'he 

 cells of the filaments are, at first, like any other cells ; but, 

 by degrees, the nucleus of each becomes changed into a 

 thread-like body, thicker at one ^nd than at the other, and 

 coiled spirally like a corkscrew. From the thin end two 

 long cilia proceed ; and, when the cells have burst, and the 

 spermatozoids are set free, they are propelled rapidly, with 

 the small end forwards, by the vibration of the cilia. These 

 spermatozoids answer to the spermatozoa of animals, and 

 represent the male element of CJiara. 



The oogonia are borne upon short stalks, the end of 

 which supports a large oval central cell or ovujii ; five 

 spirally-disposed sets of cells invest this, an aperture being 

 left between the investing cells at the apex of the oogonium. 

 When the antheridia attain maturity they burst, the sper- 

 matozoids are set free, and swarm about in the water. Some 

 of them enter the aperture of the oogonium, and, in all 

 probability, pierce the free summit of the oval central cell, 

 and enter its protoplasm ; but all the steps of this process 

 of impregnation have not been worked out. The result, 

 however, is, that the contents of the impregnated central 

 cell now called the oospore become full of starchy and oily 



