146 



MORPHOLOGY. 



a large cavity. Within each cavity there is an oval or ellip- 

 tical body, supported from the base of the cavity on a short 

 stalk. This is an antheridium, and one of them is shown still 

 more enlarged in fig. 178. This shows the structure of the 

 antheridium, and that there are within several angular areas, 

 which are divided by numerous straight cross-lines into countless 

 tiny cuboidal cells, the sperm mother cells. Each of these, as 

 stated in the former chapter, changes into a swiftly moving body 

 resembling a serpent with two long lashes attached to its tail. 



318. The way in which one of these sperm mother cells changes into this 

 spermatozoid is very curious. We first note that a coiled spiral body is appear- 



Fig. 178. 

 Section of antheridium of mar- 

 chantia, showing the groups of 

 sperm mother cells. 



Fig. 179. 

 Spermatozoids of marchantia, 

 uncoiling and one extended, sliow- 

 ing the two cilia. 



ing within the thin wall of the cell, one end of the coil larger than the other. 

 The other end terminates in a slender hair-like outgrowth with a delicate vesi- 

 cle attached to its free end. This vesicle becomes more and more extended 

 until it finally breaks and forms two long lashes which are clubbed at their 

 free ends as shown in fig. 179. 



319. Archegonial plants.— In fig. 180 we see one of the 

 female plants of marchantia. Upon this there are also very 

 curious structures, which remind one of miniature umbrellas. 

 The general plan of the archegonial receptacle (or female 



