MOSSES AND LIVERWORTS. 127 



These and other genera will furnish a full supply of mate- 

 rial for comparative study. 



The student is advised to proceed with his preliminary 

 observations as he did with the mosses, comparing a num- 

 ber of different kinds, instead of confining his attention 

 to a single species. Differences of habit between these 

 and the mosses, the bilateral and dorsi-ventral frond of 

 the liverworts, their texture and anatomical structure, and 

 peculiarities of fructification should all be noted. If the 

 mosses have already been studied Tis directed, there will 

 be little difficulty, with suitable material and the help of 

 the various manuals, in obtaining a corresponding general 

 view of the structure and habits of the liverworts. 



Many interesting subjects for more extended investi- 

 gation present themselves; among them the following 

 are suggested as 



SPECIAL STUDIES. 



I. Development of the gemmse. Lunularia offers ex- 

 cellent and abundant material for this, and its 

 gemmse, on account of their simplicity, are among 

 the best objects with which to begin studies of 

 developmental history. 



II. Comparison of the anatomy of Conocephalus with 

 that of Marchantia. The latter is selected be- 

 cause of its being so fully described in the books. 

 For the former, Lunularia or some other genus 

 may be substituted if more convenient. 



III. Rhizoids of liverworts compared with those of 



mosses. 



IV. Structure of the mature sporocarp in the different 



families of liverworts. 



