the Development of the Theca, and on the Sexes of Mosses. 507 



Fig. 11. A quaternary union of sporules in their mother-cell, somewhat ad- 

 vanced ; each sporule contains globules of fluid and a few granules. 



Fig. 12. A more advanced union of sporules. 



Fig. 13. A different view of sporules in the same stage. The two minute 

 points on the opposed faces of the upper sporules I believe to be 

 analogous to the stalks which connect the sporules of Pilularia in 

 the young state. 



Fig. 14. A sporule, which has separated from the others by the bursting of the 

 mother-cell. 



Fig. 15. A sporule, which has been separated by a forcible rupture of the 

 mother-cell, a portion of which still surrounds the sporule, but in a 

 shrivelled state, appearing as if it had been overstretched. 



Fig. 16. An instance in which only one sporule has been developed in a 

 mother-cell. I could discover no signs of the stalk or radiating 

 lines. 



Fig. 17. Ripe sporules. This is an instance where the union has not been dis- 

 solved, as it perhaps usually is at an earlier period. The surface of 

 the sporules, at least as much as is exposed, is completely covered 

 with brownish granules. There are no signs of the mother-cell. 



Fig. 18. One of the last sporules, forcibly separated to show the three radiating 

 lines and the minute stalk. No granules could be deposited on the 

 surface at this point on account of the cohesion of the sporules. 



VOL. xviir. 3 X 



