

.march, loo?.] SHIBATA & MIYAKE.—CYCAS-SPERMATOZOIDS. 47 



Experiment I. 

 ( Capillary solution: archegonial contents of Cycas. 

 (Outside solution: water. 

 Reaction very distinct : strong attraction towards the 

 mouth of the capillary tube; at first some indication of repul- 

 sion, later entering into the tube, continuing the activity in the 

 capillary fluid for at least 30 minutes. 



Experiment II. 



{ Capillary solution : same as the preceding. 



(Outside solution: 7, no mol. solution of Ca(N0 3 ) 2 

 Reaction very distinct: nearly all spermatozoids being at- 

 tracted towards the mouth of the capillary tube ; moving inside 

 the tube for more than 30 minutes. 



Experiment III. 



[Capillary solution: same as above. 



(Outside solution: \/ W{) mol. solution of sodium malate. 

 No reaction whatever. 



Now we see in the above experiments that the Equisetum- 

 spermatozoids are attracted by the archegonial contents of 

 Cycas and the chemotactic reaction is not least iufluenced when 

 the outside medium contains calcium salt, while the attraction 

 disappears by the presence of malic acid salt in the medium. 

 It is therefore highly probable that the chemotactic attraction 

 is due to the presence of malic acid in the archegonium. 



From these results we have to conclude that either the 

 Cjras-spermatozoids lack the chemotactic irritability or the 

 chemotaxis can only take place under some unknown external 

 conditions such as the special composition of outside medium, 

 If the former alternative is found to be correct, the spermato- 

 zoids have probably lost the chemotactic irritability which has 

 existed in the ancester of Cycas and perform, at present, the 

 act of fertilization by means of mechanical or some other 

 contrivances. The second alternative seems not to be very 

 probable although we are yet far from expressing any definite 

 opinion about it as we do not yet know the chemical constitu- 

 ents of the natural fluids in which the spermatozoids swim in 

 the archegonial chamber before they penetrate into the egg. 



