46 ELEMENTARY BIOLOGY. [CHAP. 



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 an- 

 theridium 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 small pro- 

 cesses of the nodal region, to their complete form. The 

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

 by degrees, the protoplasm of each becomes changed into a 

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

 coiled spirally like a corkscrew. From the thin end two 

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

 antherozooids are set free, they are propelled rapidly, with 

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

 antherozooids answer to the spermatozoa of animals, and 

 represent the male element of the Cham. 



The sporangia or spore-fruits are borne upon short stalks, 

 the end of which supports a large oval central cell; five 

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

 left between the investing cells at the apex of the sporan- 

 gium. When the antheridia attain maturity they burst, the 

 antherozooids are set free, and swarm about in the water. 

 Some of them enter the aperture of the sporangium, 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 central cell become 

 full of starchy and oily matter; the spiral cells forming its 

 coat acquire a dark colour and hard texture, and the spo- 

 rangium, detaching itself, falls into the mud. 



After a time it germinates; a tubular process, like a 

 hypha, protrudes from its open end, and almost immediately 

 gives off a branch, which is the first root (compare the ger- 



