Observations on the microscopic alga which causes the discoloration of the sea in various parts of the world / by C. Collingwood.

  • Collingwood, Cuthbert, 1826-1908.
Date:
1868
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the microscopic alga which causes the discoloration of the sea in various parts of the world / by C. Collingwood. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    they are all three spoken of as blood-red—a colour which I have never seen approached. Again, one of the generic characters of Trichodesmium given both by Ehrenberg and Montagne is “ muco involuti,” while I confidently state that no mucous envelope characterised the species so abundant in the China Sea, and which I also observed in the Indian and Atlantic Oceans. But, then, it might be said the ex- planation is easy, viz., that the China Sea Alga is of a different species from that of the Red Sea. I have no doubt whatever that this is the case, but the Alga met with by Darwin near the Abrolhos islets, which gave the sea “a reddish-brown appearance,” and which, from his description of it, was apparently the same as that I so abundantly met with in the China Seas, was pronounced by Mr. Berkeley to be Trichodesmium erythraeum, “ the same species with that found over large spaces in the Red Sea.” It is true Mr. Darwin describes it as a reddish-brown, but he elsewhere states that the endochrome was of a brownish-green—which is more suggestive of the colour, as I have always seen it. So also the substance seen by Banks and Solander in the neighbourhood of New Guinea was doubtless what I have described, and the name universally given to it by Cook’s sailors, viz., sea sawdust, exactly expresses its appearance and colour, implying, however, nothing red. With the exception, indeed, of the observations of Dr. Hinds, the blood-red Alga seems nowhere to have been met with but in the Red Sea and Arabian Gulf, and it would, indeed, be strange if the same Alga was always blood-red in the Red Sea, and yellowish-brown somewhere else. More- over, Hind’s specimens were immediately referred to a new species. Next to the China Sea, the coast of Australia appears to be the favourite locality for this Alga, though there seems, indeed, to be scarcely any part in the world in which it may not be seen in greater or less abundance.