344 SUMMARY OF CUKKENT 1IESKAKCHE8 EELATI^'G TO 



Contribution to the Study of the Verticillate Siphonese of the 

 Limestone of Villanova-Mondovi.— A3lu.ia Baretti (Att. Soc. Ital. 

 Sci. Sat. e Mus. Civ. St. Xai. Milam, 1919, 58, 216-3G, figs, in text-). 

 A determiiiatioii of the verticillate Siphonea^ from the triassic limestone 

 of Yillanova according to Pia's classification. Ten species are recorded, 

 representing three genera — Diplopora., Kantia, Teutloporella. Kantia 

 monreyaJense and K. Brunoi are described as new species. E. 8. C4. 



Researches on the Laminarias of the French Coasts.— C. SauvaCxEau 

 {Mem. Acad. Sci. Paris, 191.S, 56, 240, 85 ligs. in text). An 

 exhaustive account, with illustrations, of all the work on the subject 

 carried out by the author. In an introduction, after a short summary 

 of the work of other authors and their conclusions, the results hitherto 

 unpublished of the author's cultures of Chorda Fihim are briefly described. 

 The embryospore germinates, and the resultino- plantlet is entirely 

 comparable Avith that described for Laminaria, the swollen distal cells 

 representing a prothallus. After fifteen days two or three cells were 

 observed, which, not being of uniform size, were presumably male and 

 female. Then growth slackened off, the prothalli developed septa and 

 branched, producing short filaments of torulose or irregular gloljular 

 cells. Neither plantlets (with one exception) nor sexual organs were 

 obtained. The author suggests that the prothallia of C. FUinn at 

 Eoscoff, at least under certain conditions, may be apogamous, and that 

 the plantlets arise direct at the expense of a cell of the prothallus. An 

 examination of Dictyosiplion fmnicidaceus produced more complete 

 results. Alternation of generations takes place, but of a quite different 

 character from that of Laminaria. The zoospores produce a prothallus 

 bearing plurilocular organs, the motile elements of Avhich are isogamous 

 gametes ; the zygotes, or the parthenogenetic gametes, give rise to a 

 protonema on which appear the plantlets of Uictf/osiphou. The alga 

 known under this name is merely the sporophyte of the entire individual. 

 The two types respectively of Laminaria and Diciijosiphon re}»resent 

 doubtless the mode of reproduction followed by a number of other 

 Pha3ophycea3 ; but a difficulty still remains in explaining the seasonal 

 existence of certain epiphytes which ai)pear suddenly and abundantly, 

 grow rapidly, and disappear after fructification. The reproductive 

 elements which they disseminate cannot be those wliich germinate the 

 following season, especially when the host plant itself is ephemeral. An 

 instance of this is Litosiphon pusiUus on Chorda Filum. AVhat is the 

 intermediate stage of this and many similar species ? Other points of 

 interest in the introduction must be studied in the original work. The 

 first part of the memoir is devoted to Saccorhiza bulboaa : — 1. Geogra- 

 phical distribution. 2. Biology {S. bidbosa is an annual), o. Develop- 

 ment : sporangia and zoosjiores, male and female prothallia, etc. 

 4. Nature and origin of the tissues of the young plant. The remaining 

 parts treat respectively of Laminaria Hexic.aulis, 1j. IjejoUsii, L. Cloustanii, 

 L. saccharina, and Alaria escu.lenta ; two chapters, biology and develop- 

 ment, Ijeing devoted to each. A bil)liograp]iy and synopsis of contents 

 complete this important memoir. E. S. (1. 



