Mr. W. H. Benson on new forms of Cyclostomacea. 225 XVII. — Characters of seventeen new forms of the Cyclostomacea from the British Provinces of Burmah, collected by W. Theo-bald, jun., Esq. By W. H. Benson, Esq. I. Alycceus pyramidalis, n. s. Testa perforata, pyramidato-conica, leeviuscula, confertim oblique ar-cuato-striatula, albido-carnea, apicem versus rubella; spira pyra-midata, sutura valde impressa, apice obtusiusculo ; anfractibus 5^ valde convexis, ultimo postice inflato, turn constricto, deinde sub-tumido, aperturam versus latiori, tubulo calloso, elongate, retro-verso, suturali, pone constrictionem oriente, munito ; apertura ob-liqua, subcirculari ; peristomate dupliei, interno continue, expan-siusculo, externo expanso, reflexiusculo, anfractu penultimo bre-vissime angulatim adnato, superne antice sinuato, turn arcuato, ad umbilicum leviter emarginato. Operculo ? Long. 12, axis 10, lat. 10 mill. Hab. raro ad collem Therabuin, vallis Tenasserim. Nearly related to the Cochin-Chinese Alycceus gibbuSy Fer., but easily to be distinguished by its more pyramidal growth, and by the greater length of the spire in proportion to the breadth of the last whorl, its more symmetrical proportions, sculpture, &c. The origin of the sutural tube is about 4 milli-meters from the anterior margin of the aperture* This shell was met with at no other place in the district, and seemed restricted to a spot of a few acres in circumference. The hill is of limestone, steeply scarped and almost inaccessible. Three species of Helix occurred there which were similarly deficient elsewhere. 2. Alycceus umbomilis, n. s. Testa late umbilicata, depressa, subdiscoidea, confertim acute ar-cuatim costulata, cinereo-albida, apicem versus obtusulum, rubel-lum vel nigrum, rubescente ; spira brevi, sutura profunda ; anfrac-tibus 4^ convexis, ultimo ad latus, spiraliter rugoso-cancellatum, inflato, tum constricto, deinde tumidiusculo, tubulum retroversum, elongatum suturalem pone constrictionem gerente ; apertura valde obliqua, circulari, undata, peristomate dupliei, interiori continue, expanso, nitidissimo, prope umbilicum sinuato, exteriori expanso, incrassato, ad anfractum penultimum breviter interrupto ; umbilico perspective. Operculo corneo-fusco, nmltispirato, anfractuum mar-ginibus scabre elevatis, extus profunde concave, intus convexiusculo, nitidissimo, sulco marginate, umbene centrali papillari munito. Diam. major 10, minor 8, axis 5 mill. Hab, ad Akaoukteng, prope ripas fluvii Irawadi, nee raro. As the last-mentioned species exhibited a Cochin-Chinese form, so does this shell represent, on a larger scale, the little Western Himalayan species A. strangulatus, Hutton. The sca-Ann.^ Mag. N. Hist. Ser. 2. Fb/. xvii. 15
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