| OCR Text |
Show 608 MAJOR GODWIN-AUSTEN ON [Nov. 17, 1. Descriptions of five new Species of Helicida of the Subgenus Plectopylis, with remarks on all the other known forms. By Major H. H. GODWIN-AUSTEN, F.R.G.S., F.Z.S., &c, Deputy Superintendent, Topographical Survey of India [Received September 25, 1874.] (Plates LXXIII. & LXXIV.) The new species here described are from a collection of shells made in the Naga Hills and Munipur, when I was employed on the survey of that part of the country, which has proved so rich in Molluscan fauna. Plectopylis was established as a good and distinct subgenus of the Helicidae by Mr. W . H . Benson, in the * Annals & Magazine of N a tural History' for April 1860. I have been led to give drawings of all the species I could obtain, in order to better elucidate the interesting change that has taken place in the form of the internal barriers, and which on the examination of many specimens of local species I have found most constant. Benson's excellent paper leaves very little to be added ; but I trust the drawings now given may be useful not only as illustrative of the new species but of his paper and the forms he described, as well as those afterwards collected by M r . W . T. Blanford, and described by him in the Journ. Asiat. Soc. Beng. * The subgenus arranged under its principal physiological characters, as given in the table annexed, presents two well-marked divisions, the first of which can be further subdivided into two, and the second into three subgroups. HELIX (PLECTOPYLIS) SERICA, nov. sp. (Plate LXXIII. fig, 5.) Shell dextral, very openly umbilicated, discoid, pale horny brown, very flat above, with regular narrow oblique bands of brown crossing the whorls. Epidermis thin. The apex very slightly higher than the adjacent and outer whorls. Whorls 7, narrow and closely wound* flat above, the last descending near the aperture, which is diagonal; outer margin circular ; peristome white, reflected, continuous on the body-whorl or parietal margin. The palatal teeth, 6 in number, are situated rather more than one third the circumference from the aperture ; and, counting from above downwards, the first is very minute, the 4th, 5th, and 6th the largest. On the parietal side of the whorl there is one single vertical lamina with short bifurcations or supports above and below, Major diam. 0'50 inch, minor diam. 0*43, alt. axis 0* 16. Hab. I first collected this shell on the peak of Henozdan, Burrail * • Contributions to Indian Malacology,' No. V. Vol. xxxiv. part ii. pp. 8, 9. Vide also notes by same on a species of Plectopylis, ' Ann. & Mag. Nat. Hist.' for April 1861, ser. 3, vol. xi. p. 86. |
