Bibliography, etc.—This is just one of those cases where it is so difficult to choose between accepting names for forms which, though allied, are distinct, or simply lumping all the forms together under one specific designation, which does not exactly fit any of them. Objections more or less valid may be urged against either course, and some might be disposed to cut the Gordian knot by making new species all round. Buvignier went very closely into the varieties of the Corallian Cerithia. He points out that the true C. limœforme of Rœmer occurs rather higher than the Coral Rag, viz. in the “calcaire à astartes,” to which it is restricted. It is characterized by three rows of transverse granulations, just as shown in Rœmer’s enlarged figure, though at times a fourth or even a fifth very faint one is developed. It is difficult to say of what value these refinements may be, but certainly C. limœforme, as thus restricted, cannot be exactly identified in the Corallian of Yorkshire, where its place is occupied by forms slightly different, though in our collections they have been generally lumped together under the heading C. limœforme, Rœmer.