Mr. W. H. Benson on two species of Pterocyclos. 195 "from Sumatra" on the authority of Lafargue. A gigantic Cyclostoma appears as C. oculus Capri, from the same island, on the like authority, in the collection. Having pointed out these shells to Dr. Pfeiffer's notice, further information respecting them may eventually be obtained in the Supplement to his 1 Monograph/ Dublin, 3rd July, 1851. P.S. — Two other species have been assigned to India, C. Turbo, Ch.,andC tricarinatum, Mull. ; the former by Chemnitz, who cites Tranquebar and Coromandel as the habitat. Later observers have not confirmed this reference. Sowerby mentions Sumatra, but quotes no authority. C. tricarinatum is attributed by the last-named author to India. The form at once suggests an East African insular origin, and Petit de la Saussaye refers it to the Mauritius, citing however no authority in the f Journal de Con-chyliologie/ I am able to corroborate this statement. Sir David Barclay presented me with a worn and bleached specimen which he had himself picked up in the island at the Caverns of M. du Plessis, near the Petite Riviere; and he showed me another specimen, recently dead, which had just been brought to him from the woods. Cyclostoma Michaudi, Grat. (carinatum, Sowerby), for which no locality is given in the ' Thesaurus/ and which Petit ascribes to Madagascar, was procured by Sir D. Barclay from the Piton de la Riviere Noire in the Mauritius. They occurred with both a white and an orange peristome. In the former variety the carina? were more distant, as shown in Sowerby' s figures ; it may perhaps be found to constitute a distinct species. Dublin, July 5, 1851. XVII. — Descriptive characters of two species of the Genus Ptero-cyclos, discovered by Dr. Bland. By W. H. Benson, Esq. [With a Plate.] • In the 5th volume of the Journal of the Asiatic Society of Cal-cutta, Dr. William Bland, of H.M.S. Wolf, published, in 1836, a note on two unnamed species of Pterocyclos, to which, on inspec-tion of the coloured drawings forwarded to me by the Secretary, but unfortunately not engraved, I added a note on their affinities. Previously to returning them to Mr. James Prinsep, I took a pencil outline of the figures, for the purpose of reference, and from these outlines, with the assistance of Dr. Bland's note, I now endeavour, at Dr. PfeifFer's suggestion, to affix specific cha-racters (necessarily imperfect) to two novel forms of a rare and 13*
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