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Show 42 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [J none, except as regards a slight depression at the base. L. 0'06, B. 005. 'Porcupine* Exp. 1870: Atl. St. 36. A single and not quite perfect specimen. It is not the young of any known species of Fossarus. Since the above description was written I have ascertained, by comparison of specimens, that this species is the Coralline-Crag fossil, described and figured by the late Mr. Searles Wood under the name of Lacuna reticulata-which must therefore replace the specific name interjunctus, which I had imposed upon this form. A. Not umbilicate. 1. S E G U E N Z I A F O R M O S A , Jeffreys. S.formosa, Jeffr, in Proc. R. S. 1876, pp. 200, 201 (woodcuts) ; Ann. & Mag. Nat. Hist. 1877, p. 319 ; Journ. Linn. Soc, Zool. vol. xiv. p. 605. 'Porcupine' Exp. 1870: Atl. St. 17a, off C. Espichel, 22. Distribution. ' Valorous' Exp., off Culebra I. and Bermudas (' Challenger' Exp.), G. Mexico (Powtales), off Marocco and C. Verd I. ('Talisman' Exp.), New-England coast (Ferrill); 325- 2033 fms. Fossil. ?Miocene : Calabria (Seguenza). Pliocene : Sicily (Seguenza), Bologna (Capellini)\ Trochocochlea monocingulata, Seguenza, M S . The sinus or slit in the outer lip of this remarkable shell would seem to indicate some corresponding organization of the animal. Similar instances occur in the cases of Scissurella, Emarginula, Siliquaria, Pleurotomaria, and the Pleurotoma family. Professor Verrill proposed to make Seguenzia the type of a distinct family ; but until the animal is completely known (and not merely through the operculum and odontophore), I think it would be better to defer guessing as to the position of this genus in any scheme of classification. B. Umbilicate. 2. SEGUENZIA ELEGANS1, Jeffreys. (Plate V. figs. 1, la.) S. elegans, Jeffr. in Proc. R. S. 1876, p. 200. S H E L L globose, and forming a short cone, rather thin, semitrans-parent, somewhat nacreous and glossy: sculpture, sharp spiral ridges or keels, of which there are 4 or 5 on the body-whorl, 2 on the penultimate and next whorls, and 1 on each of the upper whorls; there are also occasional and nearly microscopic threadlike spiral striae between the ridges ; the interstices of the ridges, and sometimes the ridges themselves, are crossed by rows of minute and numerous striae in the opposite direction to the line of growth, some of these striae being curved, others oblique, straight, or alternately arranged ; in those specimens where the cross striae extend 1 Elegant. |