HOFMEISTER'S RESEARCHES. 365 



water, the result will be, that numbers of antheridia 

 will emit spermatozoa, and numbers of arcliegonia 

 will open contemporaneously. The water should not 

 be poured over the plants, but the pot should be placed 

 in water nearly up to the margin, by which means 

 capillary attraction and condensation will yield abun- 

 dance of moisture to the prothallia. After one or two 

 hours, the surfaces of the larger prothallia, which are 

 covered with archegonia, are found almost covered 

 with spermatozoa, partly in motion, and partly at rest. 

 If a delicate longitudinal section through the paren- 

 chyma of these prothallia be examined immediately, 

 with a magnifying power of from two hundred to three 

 hundred diameters, spermatozoa are sometimes found 

 in all the archegonia along the whole length of the 

 section. I thus found three spermatozoa in active 

 motion in the central cell of the archegonium of As- 

 pidium filix mas. In this case the motion ceased 

 seven minutes after the commencement of the obser- 

 vation, and was accompanied (probably caused) by 

 the coagulation of the albuminous matter of the cell- 

 contents. In the same fern on two occasions, and 

 also in Gymnogramma calomelanos and Pteris aqui- 

 lina, I have seen a spermatozoon in motion in the 

 central cell of the archegonium ; and in the above- 

 mentioned species, and also in Asplenium septen- 

 trionale, and filix fcemina, I have seen a motionless 

 body near the germinal vesicle, (after the growth of 

 the latter has commenced,) answering in form to a 

 spermatozoon. Lastly, in Aspidium filix mas and 



