1780 



Journal of Applied Microscopy 



Fig. 10. — Spermatozoid 

 swimming in 10 per 

 cent sugar solution ; 

 X 370. — After Fujii. 



tozoids. The mother cell of the spermatozoids is attached to the grain-end of 

 the pollen-tube by peculiar structure, called double cylinder by Mr. Hirase 

 (Figs. 3, 7, 8). The origin and development of the 

 double cylinder is not well understood. The similar 

 structure found in Zamia has been shown, by the recent 

 careful studies of Dr. Webber, to be double cells, the 

 central cylinder being the vegetative cell, surrounded by 

 the stalk cell, which forms the outer cylinder. Whether 

 this explanation holds true in Ginkgo or not, is to be 

 decided by future investigation. 



If we are fortunate, the first vibratory motion of the 

 cilia, the interesting movement of spermatozoids inside 

 the mother cell, the gradual increase of activity culmi- 

 nating in breaking thiough the mother cell, the more in- 

 teresting movement of the spermatozoids swimming about 

 inside the pollen-tube, and the final escape from the tube, 

 can be seen in a few hours' observation. I observed two 

 spermatozoids in active motion for two hours inside the 

 pollen-tube, and my friend, Mr. \'abe, was able to watch one kept moving for 

 three hours. 



In Zamia Dr. Webber observed a spermatozoid in constant motion for two 

 hours and fourty-four minutes. The swarm-period of the spermatozoid of a 

 fern, Gymnogramnie Marfeusii, recently studied by Dr. Buller, ^ was found to be 

 about two hours. 



For preparing a permanent mount it would be better to imbed the sperma- 

 tozoids inside the pollen-tube with a piece of nucellus attached, as it is extremely 

 diflicult to handle them after they come out of the pollen-tube. Before imbed- 

 ding it should be properly fixed. For fixing I used Flemming's weak solution, 

 Perenyi's fluid and picro-sulphuric acid solution. The first one proved to be 

 the most satisfactory. Among several stains tried Flemming's triple stain seemed 

 to be the best. After the specimen is soaked in the fixing fluid for about three 

 to five hours, it is to be washed in several changes of water for five or more 

 hours. Then stain, dehydrate, and clarify with clove-oil before finally imbedding 

 it in Canada balsam. I also found that it is sometimes better to imbed the speci- 

 men without staining. In this case spermatozoids appear brownish, due to the 

 action of Flemming's solution, and can be well differentiated from the other part 

 of the pollen-tube and the nucellus. The unstained preparation was found to be 

 much better than a poorly stained specimen. 



In closing I might mention a very interesting abnormal spermatozoid 

 found by Mr. Fujii in the fall of 1899, and reported at the meeting of the I'okyo 

 Botanical Society.- The spermatozoid has two spiral bands with a single nucleus. 

 Its sister spermatozoid developed in the same mother cell was found to be a nor- 

 mal one. This abnormal form was produced probably, as Mr. Fujii suggested, by 

 the division of a blepharoplast into two before the formation of the spiral bands. 

 I had the good fortune of examining this very interesting form in its living con- 

 dition. K. MlVAKE. 

 Botanical Laboratory, Cornell University. 



1. Buller, A. H. R. — Contributions to our knowledge of the phyisology of the spermatozoa 

 of ferns. Ann. Bot. 14 : 543-582, 1900. 



2. Bot. Mag. Tokyo, 14: 16-17, Jan., 1900. 



