given my reasons for believing that the shoal spaces within reefs of this kind, must, in many instances, have been deepened. However this may be, as several parts of this line of coast are undoubtedly fringed by living reefs, I have coloured it red.— _Maleenda_ (3° 20′ S.). In the plan of the harbour, the south headland appears fringed; and in Owen’s chart on a larger scale, the reefs are seen to extend nearly thirty miles southward; coloured red.—_Mombas_ (4° 5′ S.). The island which forms the harbour, “is surrounded by cliffs of madrepore, capable of being rendered almost impregnable” (Owen’s “Narr.” volume i., page 412). The shore of the mainland N. and S. of the harbour, is most regularly fringed by a coral-reef at a distance from half a mile to one mile and a quarter from the land; within the reef the depth is from nine to fifteen feet; outside the reef the depth at rather less than half a mile is thirty fathoms. From the charts it appears that a space about thirty-six miles in length, is here fringed; coloured red.—_Pemba_ (5° S.) is an island of coral-formation, level, and about two hundred feet in height (Owen’s “Narr.” volume i., page 425); it is thirty-five miles long, and is separated from the mainland by a deep sea. The outer coast is represented in the chart as regularly fringed; coloured red. The mainland in front of Pemba is likewise fringed; but there also appear to be some outlying reefs with deep water between them and the shore. I do not understand their structure, either from the charts or the description, therefore have not coloured them.—_Zanzibar_ resembles Pemba in most respects; its southern half on the western side and the neighbouring islets are fringed; coloured red. On the mainland, a little S. of Zanzibar, there are some banks parallel to the coast, which I should have thought had been formed of coral, had it not been said (Boteler’s “Narr.” volume ii., page 39) that they were composed of sand; not coloured.—_Latham’s Bank_ is a small island, fringed by coral-reefs; but being only ten feet high, it has not been coloured.—_Monfeea_ is an island of the same character as Pemba; its outer shore is fringed, and its southern extremity is connected with Keelwa Point on the mainland by a chain of islands fringed by reefs; coloured red. The four last-mentioned islands resemble in many respects some of the islands in the Red Sea, which will presently be described.— _Keelwa_. In a plan of the shore, a space of twenty miles N. and S. of this place is fringed by reefs, apparently of coral: these reefs are prolonged still further southward in Owen’s general chart. The coast in the plans of the rivers _Lindy_ and _Monghow_ (9° 59′ and 10° 7′ S.) has the same structure; coloured red.—_Querimba Islands_ (from 10° 40′ to 13° S.). A chart on a large scale is given of these islands; they are low, and of coral-formation (Boteler’s “Narr.” volume ii., page 54); and generally have extensive reefs projecting from them which are