248 



BOTANY. 



consists of a rounded oosphere situated within a cavity the 

 oogonium ; it is developed from one of the cells (sometimes 



two) of the filament 

 by a condensing 

 and rounding off 

 of the protoplas- 

 mic contents; when 

 the oosphere is ful- 

 ly formed, an open- 

 ing is formed in 

 the oogonium-wall 

 for the ingress of 

 the spermatozoids 

 (A and B, Fig. 

 167). One or more 

 spermatozoids are 

 produced in each of 

 certain small cells 

 which are formed 

 from the large ones 

 by a process of 

 simple fission ; in 

 shape they resem- 

 ble the zoospores 

 mentioned above 

 that is, they are 

 oval and provided 

 with a crown of 



Fig. 167^4, middle part of a t-eximl filament of CEdo- yibratile cilia Oil 

 gonium clliatum (Amlio(i>/nia of Wood), with male cellfl 



above at m; og, oogonia ^fertilized) ; HI, dwarf male their Smaller 6X- 



plants attached to the side of the oogonia, the spenna- -, / n 



tozoids already dischanred. X 260. B, oogonium, og, tremity (JJ, Z, Z, 

 at the moment of fertilization ; o. the oosphere ; , the 



at the moment of fertilization ; o. the oosphere ; z, the rp- -. R n\ T T rrm 



gpermatozoid forcing its way into the oosphere ; m. the r Ig- AU<; UIUU 



dwarf male plant. O, ripe oospore. />. (Edogonium nar>f\\\\t\ct infr flio 



f/emtllip'irumd'rin^hnmin^ VVood), part of the male C.-Caplllg mtO tne 



filament, with Hpermatozoids, u, issuing from the cells. w -lfpr which is reil- 



/;. pr.rt of a branch of Bulbocha-tt intermedia, with oojro- " ^ter, WI 



nia, the uppermost containing nn oospore, the middle dei'ed possible by 



one with an oospore escaping, the lower empty, /'.four \ J 



zooopores resulting from an oospore of Bv4bocha>te. G, a Spllttmo; of the 



Koospore come to rest and germinating. After Priugs- * , . . 



heim wall of the mother- 

 cell, they swim about vigorously, and eventually make their 

 way through the opening in the oogonium, and then bury 



