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Show 634 ON SHELLS FROM SUMATRA AND BORNEO. [May 17, 7. SCARABUS BORNEENSIS, A. Adams. Only one specimen, found at Bandjermasin. 8. PTEROCYCLOS MINDAIENSIS, sp. n. (Plate LV. figs. 8, 8a, 85.) Shell depressed, orbicular, rather solid, dark reddish brown, varied with zigzag narrow white markings both above and below, covered with a greenish-brown velvety epidermis bearing two series of close-set short hairs, one above and the other beneath the periphery, the former winding up the suture. These cilia are invariably worn off in adult shells. Whorls 5, rounded, divided by a deep suture, marked with distinct spiral striae and lines of growth. Peristome double, outer margin considerably expanded, especially at the upper part where it joins the body-whorl, but less reflexed than towards the base. Inner margin simple. Greatest diameter 19 millim., axis 5. Operculum very concave exteriorly, consisting of seven narrow whorls which are coarsely obliquely striated, with the outer margins exserted at the sutural line. This species very closely resembles P. lowianus, Pfr., from the island of Labuan. It is, however, rather larger, has a darker and thicker epidermis, which is ciliated, that of P. lowianus, as far as we know, lacking that peculiarity; and the peristome is more expanded and reflexed. The opercula of these two forms present such difference of character as to indicate at once their specific distinctness. That of P. lowianus has exteriorly a deep groove separating the whorls, which stand up erect and lamelliform. In P. mindaiensis the whorls rest one upon another, and the surface is regularly concave. HaB. Mindai (Amontai district); exceedingly common amongst the decaying leaves. Borneo is especially rich in specimens of the genus Pterocyclos. In some places, particularly at Mindai, the ground was literally swarming with Pt. mindaie?isis; they keep amongst and feed on decayed leaves. 9. OPISTHOPORUS EURYOMPHALUS, Pfr. Only two specimens from Long Wai, Koeti; one has the tube directed the opposite way. Two specimens from Mindai. 10. LEPTOPOMA (Pfr.) LOWI, Pfr. ILL. DUPLICATUM, Pfr. 12. L. BARBATUM, Pfr. 13. L. SUBCONICUM, Pfr. 14. L. MASSENA, Less. All from Mindai. Only a couple of specimens of each found. 15. CERITHIDEA (Sow.) OBTUSA, Lam. Abundant at Bandjermasin in the swamps ; they were more on land than in the river. Amongst the numbers collected I only found one with perfect apex. |