IV 
PREFACE. 
nominal list of all the species recorded as having been observed on the East African 
coast, between the Red Sea on the north and the colony of Natal on the south, in- 
cluding those from Madagascar, Mauritius, and the other islands belonging geographi- 
cally to the African continent. 
The Zanzibar dominions comprise that portion of the coast included between 
Magdashoa in 2° north latitude, and Cape Delgado in 10° 42' south latitude. 
Beyond them, to the north, are the independent Somalee tribes, which extend 
almost to the Red Sea, where they meet the Dankalie race ; and on the south they 
are bounded by Mozambique. The extent of coast under the dominion of the Sultan 
of Zanzibar is about eleven hundred miles ; but the most valuable parts of his sultanate 
are the islands of Zanzibar (containing the capital of the same name), Pemba, and 
Monfia. The first is situated at a distance of from twenty to thirty miles from the 
mainland, and is in size about equal to the Isle of Wight. It contains none but 
small streams, and, as may be expected, the number of freshwater fishes is very limited. 
Indeed, excluding those which frequent both salt and fresh water, such as Gobius and 
Eleotris , there are only two species of freshwater fish found in the island of Zanzibar, 
Clarias gariepinus and Fundulus orthonotus. The large rivers on the mainland are far 
richer in species ; but they have been very imperfectly explored, and still offer a most 
interesting field for scientific research. 
This collection contains 500 distinct species, obtained in the following localities : — 
At Zanzibar 428 
Mozambique 10 
Seychelles 27 
Comoro Islands 11 
Aden and its vicinity 23 
Chagos archipelago 1 
Of the 428 observed at Zanzibar, 192 have been noticed in and near the Red Sea, 
300 in the Indian Ocean and the seas of the more remote East, 108 on the shores of 
the various islands lying off the African coast, 7 in the Cape Seas, 3 in the Mediterra- 
nean, 25 in the Atlantic Ocean, while 63 appear not to have been found in other 
localities than the African coast or the rivers which there debouch into the sea. 
