A Government grant by the Royal Society enabled me to spend the months of August and September of 1889, in the investigation of unknown or obscure points in the marine algæ, in the Laboratory of the Marine Biological Association, Plymouth. One of my chief objects was to obtain such material of the various members of the Gigartinaceæ, of Spyridia, Stenogramme, and other genera, as would permit me to make a detailed examination of the development of the fruit (cystoearp) from the earliest stage to maturity. Several of the genera required were very rare or of unknown locality, and in many cases only to be found by dredging. In searching for these, new weeds, or new localities for known weeds, were met with, and it seemed to me the notes I made would be of use to algologists. Cocks, Hore, Boswarva, Gatcombe, &c, and of late years Holmes, have combined in their work to give a very full account of the marine algæ to be met with without the use of the dredge. For twenty years Cocks, I am told, did not miss a single low tide at Plymouth (or, if not, Falmouth). Up to the present our knowledge of the weeds of Plymouth has been derived almost entirely from shore-hunting, some of the rarest weeds being described as washed ashore, so that it was a question as to whether such weeds were locally established or merely “drift” specimens. In 1867 Boswarva published his Flora of Plymouth Sound in the Transactions of the Plymouth Athenaeum, his catalogue being compiled from the discoveries of himself, Cocks, &c. This list appears word for word in the Marine Biological Association Journal, No. 2, 1888. I am permitted by Mr. Holmes to say that through a misunderstanding he is stated to give the names of eight additional species.