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several cases, after a few applications of water in this way, jets 

 consisting of the disorganized antheridial contents were observed 

 to issue from the surface of the receptacle. With cold water, 

 the jets were rather feeble, reaching a height of about a centi- 

 meter, but when warm water was used, jets were in several cases 

 noticed which rose to heights of 3 to 5 cm., i. e., nearly as high 

 as in the case of living plants. This seems to afford conclusive 

 proof that the mechanism by which these discharges are pro- 

 duced is simply pressure due to the swelling of gelatinized cells 

 (or cell walls) on absorption of water ; that the phenomenon is 

 a mechanical and not a vital one. The presence of green as- 

 similating tissue, with air-chambers and pores, in the upper por- 

 tion of the receptacle, is probably to be regarded as enabling the 

 receptacle to supply part, at least, of the plastic materials neces- 

 sary in the development of the antheridia. This green tissue 

 can hardly be now considered as playing the part in producing 

 the discharges, by setting up an active* transpiration current lead- 

 ing to the accumulation of water in the lower portion of the 

 receptacle, which I was at first inclined to attribute to it. In 

 living plants, I have found the discharges to be quite as active 

 when the plants were placed in darkness, with slides fixed at dis- 

 tances of from 3 to 10 cm. above the receptacles, as in full 

 sunlight. In my previous observations, the plants were supplied 

 only occasionally with water, which was simply poured down 

 the sides of the vessels in which they were growing, and the 

 height to which the jets of antherozoid-containing spray rose was 

 only from 3 to 6 cm. When plants were better supplied witn 

 water, especially when this was poured or sprayed over the re- 

 ceptacles, the jets reached a height of 10 or 12 cm. in many cases. 

 I have this year observed similar, though less vigorous, dis- 

 charges in three other Marchantiaceous forms, Reboulia licvii- 

 spherica, Prcissia commutata, and Marcliantia polymorplia. In 

 most cases the antheridial contents were ejected with little force, 

 simply oozing out of the pores on the surface of the male recep- 

 tacle as drops of whitish slime, but occasionally, in all three 

 plants, well-marked jets were sent up. In Reboulia, these jets 

 frequently reached about 5 cm., but in Preissia and Marcliantia 

 none were observed over 2 cm. 



