268 On Azolla and Salvinia. 



16. Fellow of the same, the grains, (disconnected joints of 



the filaments,) have all passed out by pressure, and 

 the space between the nucleus and the foramen is 

 consequently empty. In both the early development 

 of the future yellow sac is attempted to be shewn. 



17. Part of a confervoid filament found about the base of 



this pair, 550 times. 

 18.19. Grains contained in the same: in fig. 19 these appear 

 as if inclined to coalesce ; 550 times. 

 14. Another more advanced. 



13. Fellow of the same, as usual a little more advanced : in 

 this the yellow sac was sufficiently distinct, and the 

 condensed points, the first step in the development of 

 the lobes, had also made their appearance ; 200 times. 



PI. xvi. 



(Development and mature state of the sac- containing capsule.) 



Fig. 1. Young capsule, filaments still protruding from the fo- 

 ramen ; this belongs to the second kind of formation : 

 it is a fellow of No. 4. 



2. Another of about the same period, with some para- 



physiform bodies round its base. 



3. A pair rather more advanced : the membrane of the 



(yellow) sac is now being developed; to the right 

 hand one confervoid filaments are seen adhering. 



4. Fellow of No. 1, represents the development of the 



yellow sac, and the appearance of the condensed 

 points within the nucleus above the (yellow) sac. 



5. Another similar one, more advanced. 



6. Do. do. still more advanced : this is intended to repre- 



sent that step of the development when the (yellow) 

 sac is crowned with a cap of grume, presenting nu- 

 merous condensed points, or nuclei. 



7. Another still more advanced, under slight pressure : the 



grains (disconnected joints of the filaments) have 

 almost disappeared, a membrane is developed round 

 the condensed points, (or nuclei :) the (yellow) sac is 

 collapsed accidentally. 



8. Represents the (yellow) sac and its crowning mass de- 



tached, parts displaced : (yellow) sac collapsed. In- 



