1897] NOTES AND COMMENTS 85 



two of them should he thus thrust upwards into the water, and kept 

 upright there, was a mystery. It seemed probable to us that it was 

 done to secure respiration. The sand of the shoal was literally 

 packed with these animals, and there must have been hundreds of 

 thousands or, perhaps, millions in the whole shallow." The species 

 was near or in the genus Ophiopsila. The account is extracted from 

 the miscellaneous notes in the first number of Annotationcs Zoologicac 

 Japonenscs. 



A Botanical Discovery from Japan 



Botanists became greatly excited when, several years ago, Treub 

 published an account of his discovery of Chalazogamy in Casuarina. 

 By this term, as our readers may remember (see Natural Science, 

 vol. i., p. 132) he described a method of pollination, in which the 

 pollen-tube entered the ovule through the chalaza instead of at the 

 micropyle. Treub was so much impressed with the importance of 

 this and other deviations from the normal course of events in 

 Casuarina that he separated it from the rest of the seed-plants under 

 the name Chalazogamae, the latter, in which presumably pollination 

 was effected through the micropyle, forming the Porogamae. More 

 recent work has shown this revision of our classification to be un- 

 necessary, and that Casuarina, though certainly presenting remark- 

 able anomalies, must still be retained among Dicotyledonous Angio- 

 sperms. 



There has recently come from the far East news, and confirma- 

 tion of the news, of a yet more startling discovery. S. Ikeno and 

 S. Hirase, working at Tokyo in Japan, have found that in the pro- 

 cess of fertilisation in Cycas and Gingko the male element (generative 

 nucleus) is converted before its escape from the pollen-tube, into a 

 motile spermatozoid. This swims through a epiantity of sap occurr- 

 ing in these genera between the embryo sac and the top of the 

 nucleus which forms a thin papery covering for the contents of the 

 ovule, and impregnation of the oosphere is therefore effected in the 

 same manner as in the Vascular Cryptogams. The spermatozoids 

 are much larger than hitherto known among the Cryptogams, and that 

 of Cycas is larger than that of Gingko. The shape is oval. The head 

 consists of three spiral windings in Gingko, and of four in Cycas, and 

 bears numerous motile cilia. The great importance of the discovery 

 of the Japanese botanists lies in the fact that it strengthens our 

 present system of classification. Hofmeister showed the near rela- 

 tion subsisting between Gymnosperms and Vascular Cryptogams 

 working chiefly from the development of the female spore (embryo- 

 sac) and the structures resulting therefrom. Now from the male 

 side comes a striking confirmation of his conclusions, — a confirma- 



