No entire specimen of Typhobia has hitherto been described, and we have consequently remained entirely in the dark as to the real morphological character of what is probably the most remarkable fresh-water Gastropod at present known.
Presumably from the characters of its empty shell this genus has been classed by the conchologists1 with the Melanias, as a new sub-section of that group.3 But into what serious error determinations of this sort may lead, when based on conchological evidence alone, the present paper, which contains the first anatomical description of the mollusc, will suffice to show.
It will be seen that the structural features of the Typhobias, so far from establishing the above conchological anticipations, in every way confirm the conclusions at which I arrived respecting the marine origin of these molluscs from a study of the distribution of the African lake fauna in general.3 Hence the actual...
