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 BOTANY Of these the first was detected by the late Mr. T. H. Buffham ; the second was recognized as new to Britain by Mr. Holmes, and identified as Callithamnion serpens, Crn. by Dr. Batters, and placed by him in a new genus, Hymenoclonium. The third was detected by Professor W. G. Farlow of Harvard University amongst specimens sent him from Ply- mouth. The fourth was described as new by Mr. Holmes under the name of N. tbysanorrhizans, but was subsequently found to be an Adriatic species previously described by Zanardini under the name of N. venu/osum. Elsewhere in Europe it is only known from that sea. The fifth, Punctaria crispata, was found bythe late Mr. E. George, and the sixth by the late Dr. Caspary. The general character of the Cornish Marine Alga? is that of the algal flora of the north and central French coasts, the influence of the Gulf Stream being also decidedly shown by the number of south Euro- pean species met with. Several northern species that are generally regarded as outside the flora of southern England have been reported to occur in Cornwall, but the records must be received with some hesitation until further confirmation is obtained. These are Phyllo- phora Brodicei, which Mr. Holmes has never seen further south than Anglesea ; Delesseria angustissima, not reported south of Yorkshire ; Chordaria divaricata, not collected south of Ayrshire ; Ptilota plumosa and Dictyosiphon Ekmani, which are distinctly northern species. Others, frequent on Spanish and Mediterranean shores, including Gigartina pistillata and Carpomitra Cabrera, etc., may possibly find their northern limit in this county. There are probably still many species to be detected by careful dredging off the Cornish coast, especially at Pen- zance and Falmouth, since by dredging many new species have been added to the Devonshire flora by the researches of workers in the Marine Biological Laboratory at Plymouth. The classification followed is that given in Holmes and Batters' ' Revised List of British Marine Alga; ' published in the Annals of Botany, v. 63107, with a few emendations, in accordance with the names now adopted in Engler's Naturlicben PJJanzen-Familien, but it has not been deemed useful to adopt the changes of well-known specific names as given by Dr. Batters in the "Journal of Botany for December 1902, pp. 99100, except where necessitated by the adoption of a new genus generally recognized by algologists. The species common all round the coasts of Great Britain are omitted to the number of eighty-five. The rarer species are indicated by an asterisk. The letters ' B.M.' indicate that a specimen has been seen in the British Museum by Mr. Holmes. The following species are found only in a few other counties : Bonnemaisonia hamifera, Har. Devon, Acrochjetium microscopicum, Nag. Devon, Hampshire Northumberland Calothrix parasitica, Thur. Dorset Bornetiasecundiflora, Thur. Devon, Channel Carpomitra Cabreras, Kdtz. Devon Islands Acrochaetium luxurians, Nag. Dorset, Ceramium Crouanianum, J. Ag. Devon Channel Islands CladophoraBrownii, Harv. Devon,Wicklow 83