EXPLANATIONS AND REFERENCES. 



PLATE I. 



Figures magnified 500 diameters. 



PAGK. 



Fig. 1. , GONATOZYGON AsPERUM, (Balfsii), filaments and developed zygo- 

 spore, ..... ~1'1 



" 2. " PILOSUM, ..... 22 



Figs. 3-5. HYALOTHECA DISSILIENS; three forms, normal condition, . 22 



' 6, 8. " " end views of two cells, . . 22 



Fig. 7. a cell separated from the filament, . 22 

 " 9. first stage of conjugation, one cell in 



front view, the other in end view, . 22 



Figs. 10, 11. advancing stages; chlorophyl of the 



two cells concentrating in the gelati- 

 nous connecting tube, . . .22 



Fig. 12. the developed zygospore, . . 22 



" 13. HYALOTHECA MUCOSA, . . . . . . *J3 



" 14. HYALOTHECA DUBIA, ...... 24 



" 15. BAMBUSINA BREBISSONII, . . . . . .24 



" 16. '' " a developed zygospore, . . 24 

 " 17. first stage of development from a zygo- 

 spore; undeveloped cells enclosed in 



a gelatinous envelope, . . . 24 



"18 a second condition, the gelatinous en- 

 velope largely dissipated, . . 24 



" 19. early form of a developing filament, 24 

 " '20. more advanced stage ; appearance of 



notch at the middle of the cells, . 24 



" 21. central inflation begins to show, . 24 



" 22. BAMBUSINA DELICATISSIMA, fully developed, . . 25 



" 23. " earlier stage, . . 25 

 " 24. younger still, . . . .2-") 



