TRICHODESMA ZEYLANICUM. 73rown. Grows in Abyssinia, S. Asia, and extra-tropical Australia. It is a plant of Ceylon and the Peninsula, and is the Buro kulpha of Bengal, and the Borago Zeylanica of Linnmus. Dromedaries evince an extraordinary predilection for it. T. Africanum, R. Br., and T. spinulosum, are found in the same region.— Voigt ; Von Mueller.
TRICHOM:SlifIUM ERYTHRYEUM, a fila mentous alga which the Red Sea is supposed to have obtained its natue from. It is of a blood red colour, often covers large areas, and appears and disappears somewhat capriciously. It has as synonym, T. Ehrenbergii. Daring the year 1823, Ehrenberg spent several months on the borders of the Red Sea, at Tor, very near Mount Sinai, and there witnessed the surprising phenomenon of the blood-red coloration of the entire bay, which fronts the part of that town. The open sea, outside the coral reef, was of the ordinary colour, but the short waves of the calm sea bore to the shore, during the heat of the day, a mucilaginous matter of a blood-red colour, depositing it on the sandy beach, so that in the space of little more than half an hour, the entire bay was margined by a red border many feet in width. The coloration was owing to minute, almost invisible, llocci, some greenish in colour, others of an intense green, but mostly of a deep red. The water in which they floated was, however, perfectly colourless. This very interesting phenomenon WaS investigated at leisure, durincr several days, with every possible eare. The
colouring matter was examined with the microscope. The flocci were found to be com posed of little bundles of oscillatoria filaments ; they were in shape fusiforin or elongated, were irregular, rarely more than a line long, and were invested with a kind of mucilaginous sheath. The flocci themselves did not exactly resemble one another, nor did they contain filaments. Whilst the sun was above the horizon, the flocci remained on the surface of the water in the glasses he had brought up ; during the night they sank to the bottom, or when be shook the glass, though remounting to the surface some little time afterwards. T. Hindsii, also of a blood-red colour, has been found off the west coast of S. America.
Two minute species of Triehodesmium, which have been collected in the Atlantic, imparted a cloudiness to the water over a very large area, but were not coloured. They were so diffused that it was difficult to collect the excessively minute flocci, far smaller than those at Colombo, and colotuing the sea there.
Dr. Collingwood mentions that he had never seen red Trichodesmium, or any tint of red. He had seen it yellowish-brown. He had seen the Indian Ocean red from myriads of nuinute red crustacem, and in the Formosa Channel from red gelatinous worms, but never by Trichodesmium. —Ehrenberg on the Coloration of the Red Sea, in Poggendorf's Annals ; Annals and Magazine of Natural History ; Ceylon Obserier.