THE ALG^E. 



87 



duced by the division of the cell contents into four parts 

 (Fig. 43, a); the microzoospores by the division of cell 

 contents into many parts. (Fig. 44.) 



References for Reading. Parker's " Elementary Biology," pp. 23- 

 35; Bidgood's "Elementary Biology," pp. 45-58; Dodge's "Practical 

 Biology," pp. 39-46 ; Huxley and Martin's " Practical Biology," pp. 

 389-395 ; Arthur, Barnes, and Coulter's " Plant Dissection," pp. 22-27 ; 

 Bower's " Practical Botany," pp. 439, 440 ; Bennett and Murray's 

 " Cryptogamic Botany," pp. 415-419 ; Carpenter's " The Microscope," 

 pp. 473-477. 



The Confer voideae. The plants of this class are either 

 branched or unbranched filaments of cylindrical cells, or 



FIG. 45. Chaetophora. The mode of branching is shown ; also the formation 

 of motile zoospores in maturing cells of the branches. 



are cell surfaces. The sexual reproduction is in some 

 plants isogamous, i.e., it is between elementary cells that 

 cannot be distinguished as male and female. These cells 

 are ciliated and motile ; they may develop from any of the 

 cells. The asexual multiplication is by means of ciliated 

 zoospores, which may also form in any of the cells. These 

 plants grow by the transverse division of an apical cell or 



