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Show 398 PROF. J. A. THOMSON AND MR. W. D. HENDERSON ON [Apr. 10, Towards the mouth of the Bay, on the north side, there are three fathoms of water at low tide, and here another marine Phanerogam is abundant, one with a strong hard rhizome and stems, a tuft of opposite leaves arising from the top of each of the latter. On these hard stems great quantities of bright blue encrusting forms were brought up, and among them quantities of brown Nephthyidaa, &c. The quantity and variety of these were most striking, Alcyonarians of one kind or another coming up literally by the sackful at many hauls. This spot was almost the richest in Opisthobranchs and other interesting forms that I ever dredged in. Kokotoni Harbour is a broad lake-like enclosure between the Island T U M B A T U and the north-western shores of Zanzibar. The village, now very insignificant, lies at its south-western corner. A bank in the narrow southern entrance to the channel upon which corals grow, is a garden of Alcyonarians of wonderful variety and beauty, but on the whole the shores are rather barren even of Xeniidse. Dredging reveals a current-swept bottom practically barren of all life over the greater part, but in shallower water (5 fath. and under) off the north-west shores an area of great wealth was found, where Pteroeides is common. On the mainland M O M B A S A harbour and the reefs in its vicinity are very barren, even Alcyonaria occurring but sparsely and corals being absent. Sir Charles Eliot had seen a good deal of the coast before I arrived and had selected W A S I N harbour as the best collecting-ground. This is a canal-like channel separating the island of Wasin from the mainland; the Anglo-German boundary is a few miles south of this. The richness of the shores was found to extend over the whole bottom of the channel. The dredge generally filled with Alcyonaria and sponges in a few minutes, a variety of branched and massive forms occurring in the inner or western parts about the Government station of Shimoni, while towards the open sea great quantities of a Telesto, generally more or less overgrown with a red sponge, were brought up time after time, while large colonies of Lophogorgia with commensal ophiuroids and cirripedes, the latter embedded in the coenenchyme, are common. One expects corals, not Alcyonaria, to be the most conspicuous and abundant form of animal life in tropical seas, but when it is considered that large strips of the East African shores are bare of coral, whereas Alcyonaria occur almost everywhere, and in many places with the profusion one associates with corals, their claim to be of first importance is seen to be well established. The corals are easily first in the Red Sea, where they abound practically everywhere. Alcyonaria, having the same macroscopic characters as those of East Africa, are present in magnificent abundance, but I have not seen numerous Clavulariidse, and all the Xeniida? seemed to be brown or grey, not green or blue. |