Considering the very zealous propensity of some French Naturalists of the present day, and of their admirers in England, to create new genera upon every slight occasion, it becomes a matter of some astonishment that a character so very obvious as the disjunction of the tube from the aperture to the very summit should not have laid the foundation of a new genus, for the reception of this shell. Lamarck, however, places it at the head of his _Scalaires_, and one of the next species in succession is his _Scalaria Communis_, a shell perfectly well known by every Naturalist throughout Europe for nearly a century past under the name of _Turbo Clathratus_.[20] Nor is Lamarck singular in this very anomalous consolidation of shells so distant in this respect from each other; for Cuvier in his _Règne Animal_, after describing our present shell, the Linnæan Turbo Scalaris, as one of his _Scalaires_, and informing us it is distinguished by the whorls not touching each other, adds particularly that there is another species which has not that peculiarity, and that is the _Turbo Clathratus_. Nothing, however, can be more certain than that from this very circumstance these two shells are generically distinct from each other; Clathratus may be retained with the Linnæan Turbines, but Scalaris has nearly, if not entirely as much claim to the _Serpula_[21] as _Turbo_ genus; which cannot be said of T. Clathratus. We shall for this reason allow the Wentletrap to remain where Linnæus has placed it, namely, among the Turbines; not perhaps without some hesitation, but if we did remove it, we should certainly prefer the institution of new genus for its reception, instead of wandering from one anomaly to another, as we must perceive would be the case in the present instance by following the example of Lamarck and Cuvier. It may be lastly observed that the progressive growth of this extraordinary rarity may be determined by the greater number of the longitudinal ribs that pass over and surround the tube of the whorls, for at each increase the animal forms a new mouth to its shell: the new mouth as it is protruded and formed, appears like the former ones, entirely surrounded by a rim or ring, and it is these rings of the mouths as they are formed in succession, that constitute the ribs which appear to traverse the shell as it is increased in length, and consequently in the number of its rings. Shells of a large size exhibit sometimes as many as fifty or sixty of such rings surrounding the tube or spire at regular intervals. ----- Footnote 19: _Wenteltrap_, _Wendeltrap_, Rondom gaande trap, met een spil daar al de trappen in schroeven. _Marin._ Footnote 20: _Vide_ Donovan’s British Shells, Vol. I. plate 28. Footnote 21: