172 



BOTANY. 



282. Archegonia. — If we now examine closely, on the thicker 

 part of the under surface of the prothallium, just back of the 





,, : - ••■...: V: ., ^ r '.. 



Fig. 147. 



Mature and open archegonium of fern (Adiantum cuneatum) with spermatozoids making 



their way down through the slime to the egg. 



sinus, we may see longer 

 stout projections from the sur- 

 face of the prothallium. These 

 are shown in fig. 139. They are 

 the archegonia. One of them 

 in longisection is shown in fig. 

 146. Itisflask- 

 shaped, and 

 the broader 

 portion is sunk 

 in the tissue of 

 the prothal- 

 lium. The egg 

 is in the larger 

 part. The 



KnprrnQtn7nirU ioiti fusing with'the nu- 



speimatozoias cleus of the eg(r _ (After 



Fig. 148. 

 Fertilization in a fern 

 (marattia). sp, spermato- 



Fig. 149. 

 Voting plant of Pteris serrulata still 

 attached to prothallium. 



when they are Campbell.) 



swimming around over the under surface of the prothallium 



