Sponge is found in abundance, but when dry it decays. Fine conchological collections were chiefly made in former years. The merchants spoiled the market by supplying whole cargos for watch-dials and for polishing porcelain. Slaves still fasten their canoes to the several banks in the roadstead, and find in the transparent waters the murex and other prized specimens. The harp-shell and ‘double-harp’ are found upon the softer sands enveloped in the folds of their owners; thus parasites cannot ruin their beautiful and brilliant hues. The ‘Kheti,’ or common cowrie, is picked up when the tide is out in vast quantities by the coast people, from Ra’as Hafun to Mozambique. Lieut.-Colonel Hamerton was fortunate enough in those early days to obtain two specimens of the Cypræa Broderipii, or orange-cowrie, with a stripe down the dorsum. Exaggerated ideas of its value had been spread, and it was reported that £500 had been offered for a single shell. The cowrie trade of Zanzibar was begun by M. E. P. Herz, of Hamburg. He made a daring speculation, and supplanted in Western Africa the rare and expensive Hindostan shell by the coarse, cheap Cypræa of this coast. During the last century the Portuguese used to export cowries for Angola from the Rio das Caravelhas, in Brazilian Porto Seguro. The success of M. Herz’s investment opened a mine of wealth. M. Oswald (senior), afterwards Prussian Consul-general at Hamburg, commenced as half-owner of a small vessel which shipped cowries at Zanzibar, and traded with them for palm- oil at Appi Vista, Whydah, Porto Novo, and lastly Lagos, on the Slave Coast. As the sack was bought for $O.50 to $1.44, and sold for $8 to $9, the trip cleared $24,000 (£4800), paid half in coin, half in ‘oil;’ and the single vessel soon increased to three. The owner was an excellent ship-master, who carefully supplied his employées with maps, charts, and sailing directions. He died in 1859, leaving a self-insuring fleet of 18 sail. In 1863 his sons had raised the number to 24, and they kept up large establishments at Lagos and Zanzibar.