NOTES ON THE PHYSIOLOGY OF FUCUS 

 SPERM ATOZOIDS. 



W. J. ROBBINS 

 CORNELL UNIVERSITY 



The notes here presented are of work conducted at the Marine 

 Biological Laboratory, Woods Hole, Mass., during the summers 

 of 1912 and 1913 at the suggestion of Dr. B. M. Duggar. to whose 

 kindness I also owe the opportunity and pleasure of working 

 there. 



Strasburger (i) states that spermatozoids of Fucus, passing 

 at a distance of one or even two diameters from the egg, turn 

 from their path and rush toward the egg. This attraction, he 

 says, is a chemical one and is due to some substance secreted by 

 the egg which conditions the direction of motion of the spermato- 

 zoids. Strasburger also states that healthy spermatozoids are 

 strongly negatively phototactic. These two phenomena of 

 phototaxy and chemotaxy are used by Strasburger as a basis 

 upon which to account for the meeting of the spermatozoids and 

 the ova as follows: 



The ova have a density greater than water and sink. The 

 spermatozoids, as they are negatively phototactic, swim down- 

 ward bringing them into the region where the chemotactic 

 influence of the eggs is sufficient to complete the union of the 

 spermatozoids with the. ova. Strasburger made no attempt to 

 discover the chemotactic agent. 



Bordet (2) also attempted an explanation of the same problem. 

 He filled a capillary tube with crushed ova, immersed the tube in 

 a drop of sea water containing Fucus spermatozoids, and watched 

 for evidences of attraction, but found none. From this he 

 concludes that the ova exert no chemotactic influence on the 

 spermatozoids. He observed, however, that the spermatozoids 

 were very sensitive to contact, clinging with one cilium to the 

 glass slide or any solid object as, for example, a capillary tube. 



Bordet also states that Fucus spermatozoids are not phototactic, 



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