74 SUMMARY OF CURRENT RESEARCHES RELATING TO 



both in the preparations for copulation and in the topography of the 

 copulating cells. The subject is treated under the headings : 1. 

 Notes on the morphology of the process of copulation ; (a) Spirogyra 

 neglecta ; (b) S. spreeiana. 2. Ripening of the zygotes ; (a) starch and 

 oil ; (b) the chromatophores ; (c) the nuclei. 8. Structure of the ripe 

 zygotes ; (a) contents ; (b) membrane. 4. Germination of the zygotes. 

 5. Law of numbers and reduction of the chromatophores and chromo- 

 somes. The results are set forth in a detailed summary, and a list of 

 literature is given. The paper is illustrated by a plate and text-figures. 



Sargassum bacciferum.* — ('. Sauvageau combats the statements of 

 certain authors that S. bacciferum has been found growing attached any- 

 where, and declares definitely that this is not the case. It is to be 

 regretted that the error should have been so widely accepted. The 

 original home of S. bacciferum has never been found, though the species 

 is known in such quantity in the Sargasso Sea, as well as floating in the 

 waters round Cape de Verde, the Azores, Bermuda, New Orleans, 

 Guadeloupe, Brazil, Chili, Australia, New Zealand, and Ceylon. It is 

 rarely thrown up on the shores of Europe. There are two alternative 

 theories as to this species : either it grows in a fixed state on the shores 

 of some country, whence it is wafted by currents far and wide and 

 almost entirely in a sterile condition ; or it has lived and vegetated from 

 time immemorial in a floating condition and propagated itself by 

 budding. Piccone regards it as indicating a former tract of land now 

 submerged, the ancient Atlantis. The present author suggests that 

 collectors might do something towards unravelling this mystery by col- 

 lecting and examining the plants which are growing among the drifting 

 Sargassum, since some of these might be sufficiently characteristic to 

 reveal their place of origin. 



Sexuality of Halopteris scoparia.f — C Sauvageau, the first dis- 

 coverer of heterogamic sexuality among the Sphacelariaceas, has found 

 organs resembling antheridia in dried specimens of Halopteris brachy- 

 carpa, H. congesta, and H. hordavea. So far as he could tell, the oogonia 

 are unilocular and inclose a single large oogonium. A still more inte- 

 resting discovery has been made by this author, namely that of sexual 

 organs on the well-known species Halopteris (Stypocaulon) scoparia, so 

 widely distributed in Europe, the Atlantic, and the Mediterranean. The 

 asexual organs are very common in winter, although the germination of 

 the zoospores has never been followed. In December 1903, the author 

 collected 2G examples of H. scoparia thrown up on the coast between 

 Biarritz and S. Sebastian, and preserved them without any special care. 

 On examination he found that while 25 of these had only asexual organs, 

 the other one had instead oogonia and antheridia. These organs occupy 

 the same position as the sporangia. The oogonia apparently contain 

 only one oosphere, which measures about 100/*.. In the hope of obtain- 

 ing further material bearing sexual organs, the author collected plants 

 from the warmer seas of Teneriffe, and he also examined plants from 



* C.R. Soc. Biol. Paris, lxii. (1907) pp. 1082-4. 

 t Tom. cit., pp. 506-7. 



