Dr. E. Strasburger on Fertilization in Ferns. 335 



which directs the pollen-tube in Phanerogams towards the 

 germ-vesicle. 



We liave here a proof of the fallacy of Roze's notion that it 

 is the caudal bladder of the spermatozoid which contains the 

 fertilizing matter. The greater number of these bodies had 

 already lost this appendage before they reached the archego- 

 nium ; others, which retained it at that time, lost it in the 

 mucus ; but no one carried it with it into the archegonial cell. 

 In Ceratojtterisj on one occasion, six spermatozoid s, which had 

 just escaped from their antheridium, had entered into the cen- 

 tral cell of the archegonium, after which their six bladders 

 were visible in the mucus before the mouth of the canal. 

 Having entered the canal, the coils of the spermatozoid sepa- 

 rated themselves from each other ; and if no impediment arose 

 in its course, the spermatozoid soon arrived in the central cell. 

 Here the coils were again drawn together, and its movements 

 again became free. The first spermatozoid was soon followed 

 by others : four or five were able to find room in the cell ; 

 they there moved rapidly about amongst each other; later 

 arrivals remained fast in the canal. In Pteris the number 

 was sometimes considerable ; each new comer twisted itself in 

 between those already arrived, so long as any movement was 

 possible ; at last it extended itself at full length. When the 

 canal was already full, one of these bodies was seen to insert 

 its foremost end between those previously arrived, and so on, 

 till a long chain of them was formed extending outwards from 

 the canal-mouth. In this chain a spermatozoid might be seen 

 revolving on its axis ; and sometimes one would free itself and 

 hasten away ; Dr. Strasburger has observed one hundred of 

 these bodies in a single chain in Pteris serridata ; others 

 might be seen still involved in the mucus half an hour after 

 the first had reached the central cell. 



From the facts above stated. Dr. Strasburger considers it 

 undeniable that it is the mucus which acts upon the spermato- 

 zoids ; and his opinion was confirmed by removing this sub- 

 stance from the mouth of the canal, by raising the covering 

 glass or with a needle, when the spermatozoid either remained 

 in the mucus, and perished there, or, if it succeeded in freeing 

 itself, it never more found its way back to the canal-mouth. 

 The first spermatozoid that gained the central cell, either at 

 once, or after wandering about a short time, impinged with its 

 foremost end on the transparent or germ-spot on the summit 

 of the germ-sphere, and there remained fast ; it then turned 

 quickly on its axis, and sank with its point slowly into the 

 germ-sphere ; its movements became slower ; they soon ceased 

 entirely ; it continued to pass out of sight within the germ- 



