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Show 44 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Ji Fossil. Pliocene : Lamato in Calabria (Philippi). Trochus (Solariella) lusitanicus, Fischer. An elegant and exquisitely sculptured shell. 6. SEGUENZIA LAXA1, Jeffreys. (Plate V. figs. 4, 4 a.) S H E L L imperfect, consisting of scarcely two whorls; these are cylindrical and scalariform, spirally and regularly striated : mouth nearly detached, squarish ; expanding on the inner or pillar side, and somewhat effuse or spread out at the base : umbilicus narrow and contracted, but deep. L. (apparently) 0'25, B. 0*2. ' Porcupine' Exp. 1870 : Atl. St. 16. A fragmentary specimen, but peculiar and worth noticing. Whether it belongs to the present genus, or even to the same family, may be doubtful. However, a perfect specimen will be probably discovered in future deep-sea expeditions. Family XXIII. X E N O P H O R I D ^ E. X E N O P H O R A CRISPA, Kbnig. Trochus crispus (Konig), Bronn in Italiens Tertiar-Gebilde, 1831, p. 62. 'Porcupine' Exp. 1870: Med. St. 40, 41, Rasel Amoush, 58. Distribution. G. Gascony (De Folin), Mediterranean (Deshayes), Sardinia and Bona (Tiberi), Tuscanv (Jppelius), W . Africa (v. Martens), C. Verd I. (' Gazelle' Exp.), off Sahara ('Talisman' Exp.) ; 47-486 fms. Fossil. Pliocene ; throughout Italy. ? Post-tertiary : Rhodes. X. mediterranea of Tiberi, and X. commutata of Fischer. I cannot distinguish the living from the fossil form by any valid character. The only ground of such distinction would be that usually the umbilicus is more or less open in the former and more or less closed in the latter. But of two Tertiary specimens now before me from Castel d'Arquato, for which I am indebted to the kindness of Count Angelo Manzoni, one has the umbilicus open and the other has it closed. Bronn says in his description of Trochus crispus, " Umbilico subvariabili, primum aperto, serins subsemiclauso." In consequence of having in the course of m y continued labours for more than half a century examined so many thousand, indeed 1 might say so many ten thousand, specimens of shells from different parts of the North Atlantic, I may perhaps be more inclined to unite or "lump " than subdivide or " split" species ; and if any explanation be expected from me for not having adopted all the species proposed by continental conchologists, whose power of discrimination is fully equal, if not superior, to my own, I hope to be excused by them in that spirit which is the bond of all science. M y old and much valued friend Dr. Tiberi is entitled to tbe credit of having discovered or confirmed the discovery of the present species as an inhabitant of the Mediterranean. Woodward strangely placed this genus with Solarium in the Littorina family, and he assigned to it Montfort's neme ot'PAorus; 1 Loose. |
