This common shell requires little description, and is only introduced to contrast more fully the difference between these two species: the upper part of the lip has two deep notches, which form three prominent lobes; the basal lobe is toothed, similar to the _Pterocerae_: the aperture (in those shells from the East Indies) is light pink inside. A large and fine variety comes from the Mauritia islands, having the mouth within pale golden yellow. * * * * * Pl. 135 [Illustration] STROMBUS tricornis, _Horned Strombus._ * * * * * GENERIC CHARACTER.--See Pl. 10. * * * * * SPECIFIC CHARACTER. _S. testa ponderosa, nodis longitudinaliter compressis armata; labio exteriore inflexo, margine crasso, supra attenuato et ultra spiram producto; canali truncato._ Shell ponderous, with longitudinally compressed nodules; outer lip inflexed, the margin thick, above attenuated and produced beyond the spire; channel truncated. _In young stages of growth._ _Seba_, _pl._ 62. _f._ 36, 10. _Martini_ 3. _tab._ 91. _f._ 890. _tab._ 85. _f._ 847. _Lam. Syst._ 7. _p._ 201. Var. A. Shell whitish, outer lip much produced. _Upper figure._ _Martini_, _vol._ 3. _tab._ 84. _f._ 844, 845. _Sw. Ex. Conch._ _part_ 4. Var. B. Shell varied with chesnut, outer lip shorter. _Lower figure._ _Ency. Meth._ _t._ 408. _f._ 1. _t._ 409. _f._ 2. _Martini_, 3. _tab._ 84. _f._ 843. _Lister_, 871. _f._ 25. 873. _f._ 29. * * * * * Martini was the first conchological writer who separated this species from the _Strombus Gallus_ of Linnaeus; under which name are included three shells, so remarkably different from each other, that they hardly possess a single character in common. The original name of Linnaeus I have retained to that species figured by _Seba_, _tab._ 62. _fig._ 1 and 2, and by myself in _Exotic Conchology_, _Part_ 4. _Strombus tricornis_, although figured, has never yet, I believe, been defined. Two varieties of this shell are met with; one having the attenuated process of the lip much produced, the margins folded inward, and the tip somewhat spatulate, or spoon-shaped: the colour of this variety is generally white, slightly varigated with brown stripes or irregular spots. A very fine specimen of this variety, having these characters remarkably developed, is in my own cabinet, and is figured in _Exotic Conchology_, part 4. The second variety has the process of the lip shorter, and the margins not folded; the colour usually brownish, richly clouded and variegated with chesnut; the aperture within is tinged with pale red or rosy; but that of the other variety is pure white. I believe this species inhabits the coasts of America; it is a heavy shell, and sometimes measures seven inches in extreme length. * * * * *