FERN'S. 



267 



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

 theridia. Ifthepro- 

 thaUia ha\ e not been 

 watered for a day or 

 so, we may have an 

 opportunity of see- 

 ing the spermato- 

 zoids coming out of 

 the antheridium, for 

 when the prothalUa <, . , ^ .,. fe.3°«- 



i Section or anthendia showing sperm cells, and spermato- 



are freshly placed in zoids in the one at the right. 



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 



Fig. 507. ' ' 



Different views of spermatozoids; first cloSe. But aS the SpcmiatOZOid 

 in a quiet condition; in motion . , . 



(Adiantum concinnuin). bcguis to mo\'e this coil Opens Some- 



what and by the vibration of 

 the long cilia which are on the 

 smaller end it whirls away. In 

 such preparations one mav often 

 see them spinning around for a 

 long while, and it is onlv when 

 they gradually come to rest 

 that one can make out their 

 form. 



557. Archegonia. — If we now 

 examine closely on the thicker 

 part of the under surface of the 

 prothallium, just back of the 

 "sinus," we may see 



Fig. 308. 



.. Archegonium of fern. Large cell in the 



longer venter is the egg, next is the ventral canal 



^ , . ^,-11, and in the canal of the neck are two 



stout projections trom the surface nuclei of the canal cell. 



of the prothallium. These are shown in fig. 297. They are 



