346 SUMMARY OF CURRENT RESEARCHES RELATING TO 



on the Coast of Japan," the author discusses the two prevailing currents 

 along the Japanese coasts, which may lie briefly described as a warm and 

 a cold current. The courses of these are described, and it is shown that 

 they amply account for the remarkable climatic differences at places 

 having the same latitude. The author draws up a table of distribution 

 of all the species of Fucacese, showing how fifty-nine species are dis- 

 tributed among forty-six different localities on the Japan Sea, the 

 Ochotsk Sea, and the Pacific. Then follow critical notes to all the species 

 and varieties. The novelties are Coccophora ? Imperata, Sargassum 

 setaceum, several other species of Sargassum, and a new genus, Ishige, 

 with species /. OJcamurai, founded on Pelvetia Babingtonii Okam. 

 Eighteen large plates complete this valuable work on the Japanese 

 Fncaceae. 



Nereocystis and Pelagophycus.* — W. A. Setchell has made a study 

 of the two alga?, N. Luetkeana and Pelagophycus giganteus, and sets 

 forth his results. He discusses the views of Frye as to the length to 

 which the former species may attain, 21 m., and is more inclined to 

 believe Mertens, who gives 90 m. as the extreme length of the thallus. 

 The longest specimen ever seen by the author was 41 m. long. It is 

 often found growing anchored by its holdfasts to other members of 

 Laminariaceae, particularly to Pterggophora califomica. Setchell differs 

 from Frye as to the duration of life of the individual plant, and states 

 his opinion that N. Luetkeana is an annual plant. The early stages 

 appear in February or March, and the plant passes through its growth 

 and fruiting by November, disappearing in December or January. 



The author then turns to Pelagophycus, and quotes some extracts 

 from old authors of the -eighteenth century alluding to a marine plant 

 called Porra. One of these, Le Gentil, in " Voy. dans les Mers de 

 l'lnde," Paris, 1781, gives an excellent drawing of Porra, which shows 

 it to be the Pelagophycus giganteus Aresch. The name is therefore 

 altered in the present paper to P. Porra, and the reasons of the author 

 for maintaining Pelagophycus as a separate genus are given. 



Colpomenia sinuosa in Britain.f — A. D. Cotton records the first 

 appearance of this alga on the shores of Britain. It has been found by 

 himself at Swanage and by Holmes at Torquay during last year. Up 

 to within the last few years it was not known further north than Cadiz, 

 but since then it has migrated up the French coast, where it causes great 

 anxiety to the oyster cultivators, as it interferes seriously with the 

 oysters in a manner described by various French authors, and noticed 

 in past numbers of this Journal. The present author points out the 

 external likeness between Colpomenia sinuosa and Leathesia difformis. 

 In structure, however, C. sinuosa may be distinguished by the thinner, 

 non-gelatinous walls and by the structure, which is cellular, and not 

 filamentous.. Leathesia also is usually irregularly lobed, even when quite 

 young, and has a resiliency which is lacking in Colpomenia. Figures are 

 given of the structure of both species. 



* Bot. Gazette., xiv. (1908) pp. 125-34. 



t Kew Bulletin, 1908, No. 2, pp. 73-7 (3 figs.). See also Journ. Bot., xlvi. 

 (1908) pp. 82-3. 



