80 . 



cells are set free and then commence a constant rotation round 

 their axis, sometimes to the right at others to the left. The 

 enveloping vesicle appeared at times to be absent, and I then 

 thought I could perceive that the Spermatozoa moved in a 

 spiral direction. As these observations were made on a tour 

 to the Tyrol, the last circumstance could not be exactly made 

 out ; subsequently, however, I have convinced myself that in 

 the Jungermannice and in mosses the Spermatozoa quit the 

 cells at a certain period of their development and then move 

 in numerous ways, but generally determined by the spiral ro- 

 tation of their tail. The Spermatozoa of the species of Sphag- 

 num which have been so accurately observed by M. Unger are 

 also developed, as I have noticed, in the cells ; but I have not 

 been able to perceive their division as stated by M. Unger, al- 

 though I have recognized it in the Spermatozoa of animals. 



In the splendid work of M. Lindenberg* there is also a 

 chapter on the development of the female organs of fructifica- 

 tion of the Riccice, whence it is concluded that the Riccia have 

 no distinct permanent disk, but the whole frond must rather 

 be considered as such, and the last cellular layer beneath the 

 epidermis is the spot where the fruit at the time of maturity 

 momentarily dwells, or as in the Corsiniae arrives there even 

 previously. The formation of the fruit begins quite deep, 

 immediately above the under epidermis of the frond a small 

 dark spot originates which appears as a cavity, around which 

 the cellular tissue is compressed. This spot soon exhibits a 

 distinct yellowish-white membrane which forms a globular 

 sac, and is provided with an apex. In this sac are deve- 

 loped the disk-like bodies, whence the spores originate. The 

 fruit, however, in its further development gradually ascends, 

 while the cavity which was occupied by it in its earlier stages 

 is again closed by the expansion of the cellular tissue. The 

 fruit of the Riccics consists of two membranes, an inner the 

 true sporangium, and an outer the pericarpium, which, like a 

 calyptra, falls off when the spores have become ripe. In 

 Sphterocarpus and Oxymitra the outer tunic separates entirely, 

 it becomes a distinct coat, and the calyptra then again ap- 

 pears as a membrane coherent with the sporangium in the in- 

 terior of that tunic. At the formation of the spores in the 

 * 1. c. p. 392404. 



