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Show 448 MR. W. T. BLANFORD ON OPISTHOSTOMA. [Nov. 22, Southern India in 1857. The rediscovery of the genus is none the less fortunate, that specimens of the original species are so excessively rare that it has been impossible to distribute them so as to make the form known in Europe. I have on two separate occasions, in 1859 and 1864, searched the neighbourhood of Pykara, on the Nilgiris, without success, and, owing to an unfortunate accident, by which most of the original specimens were lost, I believe that but two now remain, one of which is in my own collection, and another in Mr. Benson's. Several specimens of the new species have, fortunately, been obtained; and it is to be hoped that the number may be increased, as the locality is easy of access. The new form is a very near ally of O. nilgiricum*, H. Blanf. (PI. XXXVIII. fig. 13), but still readily distinguished by several not unimportant characters. Specimens have, fortunately, been obtained living, enabling me to complete the characters of the genus, and to confirm the opinion expressed by m y brother, in our joint paper, of its being an operculated form. Although I have not succeeded in examining the animal so closely as 1 could have wished, I have been able to note the form of the tentacles, with the position of the eyes, and to see the operculum. All tend, I think, to bear out the views I expressed, in 1864f, as to the affinities of the genus. Before proceeding to any further remarks, it will be well to describe the new species, and to give the generic characters as now ascertained. OPISTHOSTOMA, H. Blanf. Testa anguste umbilicata, umbilico interdum ab anfractu ultimo obtecto, irregulariter puparformis, costulata, anfractibus api-calibus deflexis, anfr. ultimo constricto ibidem angulo acuto deflexo, retro curvato, denique sinistrorsum ascendente. Apertura retrorsa, circularis vel subcircularis. Operculum tenue, corneum, concentrice paucispirale, profunde retractum. Animal tentaculis brevibus, cylindricis, obtusis, oculis ad basin externum tentaculorum sessilibus, lateraliter positis sed Cyclo-phoridarum altioribus. Pes brevis. Proboscis brevissima. OPISTHOSTOMA FAIRBANKI, n. sp. (PI. XXXVIII. fig. 14.) Testa irregulariter ovata, albida, confertim costulata, lineis impressis spiralibus minutis, vix sub lente, conspicuis, sarpe obso-letis, inter costulas signata. Spira breviter subcylindrica, apice perobtuso, sutura profunda. Anfr. 5, rotundati, duo apicales parum exserti, ex axi deviantes, tertius multo major, quartus maximus, quintus brevissime constrictus, ad stricturam angulo acuto versus umbilicum deflexus, in flguram liter ar S curvalus, umbilicum omnino tegens, denique sinistrorsum ascen-dens, anfractus penultimus undique junctus. Apertura postica, * Described and figured in the ' Journal of the Asiatic Society of vol. xxix. p. 121, 1860. The figures are very good. f Ann. and Mag. Nat. Hist. ser. 3. vol. xiii. p. 444. |