OCR Text |
Show 132 MR. G. NEVILL ON THE [Feb. 17, CLAUSILIA (IPHIGENIA?) BIZARELLINA, Bourg. Hist. Clausil. France, 1877- I am indebted to M . Bourguignat for the above identification. Specimens of this group abounded in countless curious varieties (? species) in all the deposits A, B, C, D, E, and F. W e did not find any living forms of this subgenus ourselves; but numerous species have been described from the higher elevations in the neighbourhood by Risso and Bourguignat. CLAUSILIA (IPHIGENIA?), sp. A certainly distinct-form from the preceding, and which I only found in deposit D. As I have already said, it is hopeless to attempt to identify these species without figures. There can be little doubt this is one of the many new species of this group described by M. Bourguignat, loc. cit., from the department. CLAUSILIA (subgenus ?) PAULUCCIANA, n. sp. (Plate XIV. fig. 1.) Testa parva, rimata, fusiformis, tenuiuscula, cornea, haud nitens, ac eleganter costulata, costulis distantibus, subrectis; apex obtusiusculus, turgidus et quasi mamillatus; anfractus 10, supremi 3 convexi, Icevigati, tumidi et mamillati, 3 sequentes plus minusve convexi, sensim crescentes, 4 ultimi subtumidi, convexi, fere cequales, ultimus subglobulosus, oblique rugoso-basi acute ac distanter cristatus; apertura subpyrifor-mis, haud eversa, lamella parietali superiore subrecta, plica spirali inconspicua; lamella parietalis inferior valde ascendens, remota, postice subbifurcata; plica subcolumellaris immersa, inconspicua plica palatalis unica, supera, sat conspicua; perist. sensim solutum, continuum, expansiusculum ac reflexiusculum. Long. 8}-9, diam. 2; apert. long. 1| millim. This charming little species appears to have been very rare. However we managed to procure about thirty specimens after much searching. It only occurs in deposits B and C. It is one of the most distinct and curious of all the Western-European forms. It varies a trifle in the greater or less convexity of the whorls; otherwise it appears to be wonderfully constant, especially as regards the three peculiar apical whorls, the general sculpture, and the aperture. The apical whorl is small and subobtuse, the next two swollen, tumid, and submamillate, all three being perfectly smooth; the next two are smaller (more contracted), regular, scarcely convex, and of almost equal size; the other five whorls are more or less rapidly swollen, the last three being of approximately equal height. The last whorl is more or less subgiobose (varying somewhat); the sculpture is fairly constant, the last seven whorls being beautifully and distinctly costellated with nearly perpendicular, distant, subacute ribs ; these on the last whorl, however, become more oblique, aud near the peristome are very acute (" cristate " as it were). The aperture is detached from the last whorl in a very characteristic manner, though not everted ; it becomes in old specimens sub-callose. |