(_c_) The _East African Province_ extends from about Delagoa Bay to the Abyssinian shores of the Red Sea. In general out-line the province consists of a flat marshy district, extending inland for many miles from the sea; this is succeeded by rising ground, which eventually becomes a high table-land, often desolate and arid, whose line of slope lies parallel to the trend of the coast. The Mollusca are little known, and have only been studied in isolated districts, usually from the discoveries of exploring expeditions. The _Mozambique District_, from Delagoa Bay to Cape Delgado, includes no genus which does not occur on the west coast, except _Cyclostoma_ (2 sp.). _Trochonanina_ (4 sp.), _Urocyclus_, a characteristic African slug (2 sp.), _Rachis_ (6 sp.), _Pachnodus_ (2 sp.), and _Achatina_ (5 sp.), are the principal groups. [Illustration: FIG. 218.--_Urocyclus comorensis_ Fisch., Comoro Is.: =G=, Generative orifice; =M=, mucous gland; =O=, orifice leading to internal shell; =P=, pulmonary orifice; =T=, tentacles. (After Fischer.)] The _Zanzibar District_, from Cape Delgado to the Somali country, has the same general features. _Meladomus_, a large sinistral _Ampullaria_, is characteristic, while _Cyclostoma_ (5 sp.) becomes more abundant. _Helix_ is still absent, but the carnivorous forms (_Streptaxis_ 2 sp., _Ennea_ 7 sp.) are rather numerous. The _Somali District_ is characterised by operculate groups of the _Otopoma_ type (_Georgia_, _Rochebrunia_, _Revoilia_) whose generic value is rather doubtful. _Petraeus_, in an Arabian type, supplants _Rachis_ and _Pachnodus_. _Achatina_ is nearly wanting, but _Limicolaria_ has 9 species. A few _Helix_, said to be of the _Pisana_ group, occur. The _District between the Great Lakes and the coast region_ is fairly well known through recent explorations, especially those associated with Emin Pasha. _Streptaxis_ (6 sp.) and _Ennea_ (24 sp.) are numerous, _Helix_ is wanting, and the Naninidae are represented by _Trochonanina_ (7 sp.), and other forms at present grouped under _Nanina_ or _Hyalinia_. On the high ground _Buliminus_, _Cerastus_, and _Hapalus_ replace, to some extent, the _Achatina_ and _Limicolaria_ of the marshy plains. Land operculates (_Cyclophorus_ 1, _Cyclostoma_ 8) are more numerous; among fresh-water genera we have _Lanistes_ (5 sp.), _Cleopatra_ (3 sp.), _Meladomus_ (1 sp.), and _Leroya_, a sinistral form with the facies of a _Littorina_. The characteristic African bivalves (_Mutela_, _Spatha_, etc.) are few in number.