OF ARTS AND SCIENCES. 



63 



EXPLANATION OF FIGURES. 



Fip. 1. Typical form of frond. X l\v about 3 diam. 

 " 2. Lobed cystocarpic frond. X by about o diam. 



" 3. Very young frond just making its way into tbe Polysiphonia. X 180. 

 " 4. Somewbat older stage, where cells are nnorc regularly arranged. X 200. 

 '■ 5. Terminal cells of growing frond, from macerntion preparation. X 350. 

 " 0. Diagrams showing method of growtli of terminal cells. 

 " 7. From a preparation slirunk in glycerine to show connection of cells of 



parasite with host. X 150. 

 " 8. Vertical section of tetrasporic frond. X 150. 



" 9, 10, and 11. Three stages in the development of tetraspore. X 350. 

 " 12. Adult cruciate tetraspore. X 350. 

 " 13. Adult tripartite tetraspore. X 350. 

 " 14. Vertical section of cystocarpic frond. X 150. 

 " 15 and K!. Sliowing the two ways in which the carposporcs are borne. 



X 350. 

 " 17. Portion of periphery of cystocarpic frond, showing chains of cells. 



X 350. 

 " 18. Young procarp. X 600. 



tr, trichogyne. 



a, a,' a," trichophoric cells. 



b, carpogenio cell. 



c, undeveloped terminal cell. 



" 19. Older procarp with fully developed trichogyne. X 600. 



References as in Figure 18. 

 " 20. Procarp in which carpogenic cells have begun to develop. References 



as in Figure 18, except b', b", b'", which are the cells newly formed 



from tlie carpogenic cell b. X 600. 

 " 21. More advanced stage in development. References as before, b"", b^, 

 etc., are the result of further proliferation of cells b, b', etc. X 600. 



Figures 1 and 2 were drawn free hand. The others were all drawn with the 

 camera, except Figure 6, which is merely a diagram. Figures 18 to 21 have been 

 reduced one third from the original drawings. All the drawings are from fresh 

 material except Figures and 7, the latter of which was drawn from a section 

 shrunk in glycerine. 



