FEJiNS. 



I8l 



tered over this portion of the prothalhum. These are the an- 

 theridia. If the pro- 



thallia have not been ^^^ .^ / 



watered for a day or 

 so, we may have an 

 opportunity of see- 

 ing the spermato- 

 zoids coming out of 

 the antheridiura, for 

 when the prothalha <, ,. , ,^ ._,. p^:'"'- „ , 



^ bection or anthendia showing sperm cells, and spermato- 



are freshly placed in ™'<'= ™ "^= °"<= ^' ">^ "gi"- 



water the cells of the antheridium ab- 

 sorb water. This presses on the con- 

 tents of the antheridium and bursts the 

 cap cell if the antheridium is ripe, and 

 all the spermatozoids are shot out. 

 We can see here that each one is 

 shaped like a screw, with the coils at 



Different views of spermatozoids; firSt cloSe. But aS the SpermatOZoid 

 42, 43, in a quiet condition; 44, in , . . . ., 



motion (Adiantum concinnum). DCgmS tO mOVC thlS COll OpcnS SOme- 



what and by the vibration of 

 the long cilia which are on the 

 smaller end it whirls away. In 

 such preparations one may often 

 see them spinning around for a 

 long while, and it is only when 

 they gradually come to rest 

 that one can make out their 

 form. 



373. Archegonia. — If we now 

 examine closely on the thicker 

 part of the under surface of the 

 prothallium, just back of the 



, , , Archegonium of fern. Large cell in the 



"sinus, we may see longer venter is the egg, next is the ventral canal 



^ , cell, and in the canal of the neck are two 



stout projections irom the surface nuclei of the canal cell. 



of the prothallium. These are shown in fig. 214. They are 



Fig. 224. 



