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Show 152 DR. o. p. V O N MOELLENDORFF O N [Feb. 20, 18. HYPSELOSTOMA STRIOLATUM, sp. nov. Owing to the bad state of preservation of the two specimens of this form, quite distinct from the preceding one, I cannot give a complete description of it. Its last whorl is much more detached than in H. transitans and distinctly bent upwards, and shows very distinct though minute spiral lines. The diameter is only 2-5 millim. It belongs to the group of H. bensonianum and H. hungerfordianum. Fam. ASICULID^E. 19. TRUNCATELLA VALIDA, Pfr. 20. TRUNCATELLA SEMICOSTATA, MOUSS. Fam. CYCLOPHORID.E. 21. OPISTHOPORUS SETOSUS, sp. nov. (Plate XVI. figs. 14, 15.) T. latissime umbilicata, cliscoidea, tenuis, transverse coufertim costulato-striata, setis brevibus densis deciduis hirsuta, ; spira vix prominula, apice submucronato. Anfr. A\, teretes, sutura profunda disjuncti ; ultimus paullum descendens, pone aperturam tubulum suturalem brevem ad anfractum pen-ultimum recurvatum gerens, turn subsolutus. Apertura sat obliqua, subcircularis; peristoma duplex, internum tenue, breviter porreclum, externum expansum, campanulatvm, superne ad insertionem breviter auriculatum. Operculum extus fere planum, lamina calcarea anfr. 8 transverse costulo-striatis, sulco profundo ab interna tenui cornea separata. Diam. maj. 14, min. 10-5, alt. 5-5 millim. Forma conoidea : minor, arctius umbilicata, spira magis elevata, anfractus ultimus magis descendens, longius solutus. Diam. 11*5, alt. 7 millim. In size and general outline this species agrees somewhat with 0. corniculum of Java, but the spire is still flatter, the position of the sutural tube is different, and the hirsuteness distinguishes it from the Javan and from all other known Opisthopori. 22. EHIOSTOMA HOUSEI, Haines. Three specimens of a fine large Rhiostoma agree very well with the diagnosis of this Siamese species, of which I cannot compare either examples or figures. The largest specimen measures 28 millim. in diameter and is 16-5 high, the operculum is 8-5 millim. wide, 3 high. 23. EHIOSTOMA ASIPHON, sp. nov. (Plate XVI. figs. 16, 17.) T. late et perspective umbilicata, convexo-depressa, solida, plicato-striatula, cinerascenti-brunnea, interdum indistincte et tceniata ; spira parum elevata, apice subacute Anfr. 5, perconvexi ; ultimus antice solutus et defiexus, in parte superne albo-carinatus. Apertura obliqua, circularis ; peristoma valde incrassatum, multiplicatum, superne intus leviter incisum, extus in alam rccedentem hand tubulum formantem pjroductum. |