INTRODUCTION. 15 



very fine cilia, by means of which the antherozoids 

 rotate in water. It may be observed that some 

 authors apply the name of spermatozoids to the 

 same bodies as are here called antherozoids. The 

 male inflorescence, in its entirety, is called andrcB- 

 cium, and the bracts, or modified leaves, will 

 probably be larger than the ordinary leaves. A 

 good example of thiswill be found in Jungermannia 

 Pearsoni. 



As already intimated, there are certain modifi- 

 cations of the above general remarks on repro- 

 duction to be found, not only in the other orders, 

 but also in the thalloid or frondose Jungermanniecs. 

 Of these we can only allude to one or two of the 

 more important. 



In Marchantiacea the vegetation is frondose, 

 and special stalked receptacles have the antheridia 

 immersed in the upper surface. The female 

 receptacle is also stalked, the expanded apex 

 being variously lobed, and the archegonia are 

 produced on the under surface. Most of the other 

 details are modified in the different genera. 



In the Ricciacece, which are also frondose, and 

 sometimes floating, the reproductive organs are 

 produced on the upper surface. The antheridia 

 are immersed in the substance, showing but a 

 slight conical elevation above them. The arche- 

 gonia are also imbedded; and very simple in their 

 character, they project at first, and when fertilized, 

 the globose sporogonium becomes packed with 



