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Show 674 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Nov. 14, 2. PROPILIDIUM SCABROSUM \ Jeffreys. (Plate L. fig. 6.) S H E L L roundish-oval, expanded, rather thin, semitransparent and of a dull hue : sculpture, numerous but not close-set, slight striae which radiate from the beak and are more or less covered with short tubercles, especially behind ; there are also several concentric ridges as in the last-named species: colour whitish : beak small, pinched up, incurved, and forming a minute spire of two whorls: mouth roundish-oval: margin thin : inside glossy : septum thick and strong. L. 015, B. 0*15. ' Porcupine' Exp. 1870: Med. St. Adventure Bank. A single specimen. Differs from P. ancyloides in being round instead of oval, and in having much fewer and tuberculated striae; but I am not quite satisfied that it is more than a curious variety. It somewhat resembles the young of Gadinia garnoti; but that shell has not the internal septum which is characteristic of the present genus. 3. PROPILIDIUM PERTENUE2, Jeffreys. (Plate L. fig. 7.) S H E L L oval, convex, very thin and delicate, transparent, and glossy : sculpture, none : colour whitish: beak small, cylindrical, and incurved, forming a minute spire of two whorls : mouth oval : margin even ; inside glossy : septum small. L. 0*1, B. 0*075. 'Porcupine' Exp. 1870: Atl. St. 17, 17 a (4 specimens); Med. off Rinaldo's Chair (I specimen). Distribution. Palermo (Monterosato); 162| fms. The young of P. ancyloides, much smaller than the species now described, are more expanded or depressed, and have the same sculpture as the adult; they are also proportionally solid as well as of a dull hue. The inner layers of most of the specimens are permeated by a microscopic and branching spore-like organism, perhaps of a fungoid nature. An imperfect specimen of another small and apparently distinct species occurred also in Station 17- It has the characteristic septum, but otherwise resembles a Lepetella. The beak is very much shorter than in P. pertenue; and the spire has barely one turn. I had originally given the species above described the M S . name tenue. 4. PROPILIDIUM COMPRESSUM3, Jeffreys. (Plate L. fig. 8.) S H E L L differs from P. pertenue in being oblong instead of oval, and in being laterally compressed like Patella [Lepetellaf\ latero-compressa of Rayneval, a Monte-Mario fossil and, according to Dr. Tiberi, living in the Bay of Naples; and it is also not quite smooth, but is marked by a few slight longitudinal striae; the beak is proportionally longer, somewhat twisted to one side, and nearly overhangs the hinder margiu, instead of being placed (as in P. pertenue) at about one third of the distance from it. L. 0*1, B. 0*065 'Porcupine' Exp. 1870: Atl. St. 17. A single specimen. 1 Eoughened. 2 Very thin or slight. 3 Pressed together. |