The very important addition to our knowledge of the Belemnitidæ contained in Professor Huxley's Memoir on Xiphoteuthis encourages the hope that, by following the steps of Mr. Day, we may clear up some other perplexities among the Cephalopoda of the Lias. One of the singular forms which presents itself for more complete inquiry is the fossil called by Mr. J. Sowerby Belemnites pistilliformis, found at Lyme-Regis. It is not the species so named by Blainville, which belongs to quite another part of the series of strata. The phragmocone is as yet undiscovered. If a considerable number of specimens be examined, including varieties of figure—club-shaped, fusiform, and subcylindrical,—there will appear enough of resemblance to the guard of Xiphoteuthis to suggest the probability that the phragmocone might be slender and elongate as in that fossil. The same idea has, indeed, already been expressed by Quenstedt (‘Der Jura’) in reference to Bel. clavatus, Blainv., a fossil rather common in the Lias, and which is probably identical with Bel. pistilliformis of Sowerby. Quenstedt expressly proposes to join Orthoceratites elongatus of De la Beche, which was unprovided with a guard, with Bel. clavatus, still deficient of a phragmocone. And, in addition to the English example of that phragmocone from Lyme, he figures (‘Der Jura,’ pl. 17, fig. 9) another, having similar general characters, from the Lias of Heckingen.