The Tanganyika problem; an account of the researches undertaken concerning the existence of marine animals in Central Africa . Fig. 3.—Semi diagram of the anatomy of Typhobia Horei. The Mantle is cutopen and the animal viewed from above. The nerves are represented inblack, cryst. s., style sac, si., stomach, s/11., gill. work shall be understood to supersede any others which Ihave already published. In what follows there will befound, in the first place, a description of the structureexhibited by each of the different halolimnic molluscs,and, in the second, a discussion of their affinities, ba
The Tanganyika problem; an account of the researches undertaken concerning the existence of marine animals in Central Africa . Fig. 3.—Semi diagram of the anatomy of Typhobia Horei. The Mantle is cutopen and the animal viewed from above. The nerves are represented inblack, cryst. s., style sac, si., stomach, s/11., gill. work shall be understood to supersede any others which Ihave already published. In what follows there will befound, in the first place, a description of the structureexhibited by each of the different halolimnic molluscs,and, in the second, a discussion of their affinities, based THE TANGANYIKA PRO B J JIM. 223 on what we now know about the prosobranchiate molluscain general. TYPHOBIA, SMITH. T. IIOREI (FIG. 2). The genus TypJiobia is represented solely by the uniqueform T. horei which occurs generally in the deep water ofTanganyika, in a hundred fathoms and upwards, and onthe muddy portions of the floor of the lake. The animalwhich is of considerable size possesses the remarkable shellrepresented on page 221, and the conchological characters. Fig. 4.—Lingual dentition of Typkobia horei. A single row of the teeth onthe left side. ( X 150.) which different individuals display may vary , like all the remaining halolimnic gastropodsis prosobranchiate, and the mantle cavity presents thesame arrangement of the parts which is usually found inthe less specialised Taenioglossa, Aporrhais for is one gill (Stenidium) composed of simple triangularleaves and below this a long rope-like osphradium (Fig. 3).The renal aperture is at the extreme upper end of themantle cavity, and the intestinal and reproductive aperturesopen on the right, and on the extreme front of the mantle 224 THE TANGANYIKA PROBLEM. skirt. The snout is short, wrinkled, and pigmented, andthe eyes, which possess lenses, are situated on a longtapering tentacle on each side of the head. The buccalmass in Typhobia is not large, and the rasping teeth whichare arrange
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