235 



hese another thallose liverwort such as Metzgeria may be used. 

 In this plant the gemmae are borne abundantly on the, slightly 

 incurved margins of the thallus. 



Fig. 2. Cross-section of male gametophyte of Pallavicinia Lyellii, showing an 

 antheridium. 



For the study of the capsule and the relations of its contents 

 I have found nothing that approaches Friillania virginica in 

 clearness. Here, the elaters extend the entire length of the 

 capsule and alternate with single rows of spore mother-cells. 



Fig. 3. Diagram of young sporophyte and Fig, 4. Diagram of sporophyte of 

 surrounding parts of Fi-ullania virginica. Frullania virginica. (Spores 



represented in two middle rows 

 only. ) 



The homologous origin of these two elements is thus very clearly 

 brought out, especially if a younger stage be studied. In Fig. 3 is 

 shown a capsule of this species at an early stage. The spore- 

 bearing portion is represented by a palisade of long undivided 

 cells not yet differentiated into elaters or mother-cells. This sec- 



