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Show 286 MR. E. A. SMITH ON THE [Apr. 1, tenuis; anfractus 5, convexi, microscopice spiraliter striati, sutura subprofunda sejuncti; apertura ovata, superne paulo acuminata, longit. totius \ subcequans; peristoma tenue, continuum, margine columellari anguste reflexo. Louqit. 3-3 millim., diam. If. The spiral striae are so fine that they can only be seen under a compound microscope. Under a simple lens the surface appears smooth. Couthouyia plicifera, A. Adams, has the aperture more distinctly channelled anteriorly, and the umbilicus defined by a carinate margin. D I A L A FUSCOPICTA. (Plate X X I . fig. 20.) Testa minuta, imperforata, conica, tenuis, nitens, albo-pellucida, striqis fuscis longitudinalibus, et zona interrupta lactea ad peripheriam picta ; anfractus 5, vix convexiusculi, primi duo spiraliter tenuiter striati, cceteri Iceves, ultimus in medio rotunde angulatus; apertura mediocriter magna, longitudinis totius \ vix cequans; labrum tenue; columella rectmscula, leviter obliqua, antice subeffusa. Lonqit. 2\ millim., diam. \\. This pretty little shell has the surface smooth, with the exception of the first two whorls, which are finely spirally striated. The upper extremities of the brown stripes do not extend quite to the suture, and on the body-whorl pass between the opaque-white row ot dots at the periphery. RISSOINA MELLISSI. (Plate XXIII. fig. 34.) Testa ovato-turrita, alba, solidiuscida; anfractus sex, supremi duo convexiusculi, spiraliter striati, cceteris superne tabulati et rotunde angulati, costis validis circiter 11 {in anfr. ultimo ad basim continuis) instructi, striisaue spiralibus tenuissimis sculpti; apertura oblique ovata; labrum incrassatum, duplex, superne subsinuatum; margo columellaris callo reflexo, superne labro juncto, indutus. Longit. 3 millim., diam. l^. This is a strongly costate species, with very fine transverse striae on and between the ribs. The outer basal margin of the aperture has a double lip, and the ribs are more or less regularly continuous up the spire. RISSOINA T U R T O N I . (Plate XXIII. fig. 35.) Testa gracilis, turrita, alba; anfractus 6-7, convexi, sutura obliqua sejuncti, primi duo spiraliter lirati, ca?teri costis longitudinalibus 10-12 tenuibus, oblique curvatis, instructi, transversim, inter costas teuuissime striati ; apertura obliqua, parva, longit. totius \ vix cequans, adbasim late effusa; labrum mediocriter incrassatum, intus longitudinaliter striatum; columella obliqua, parum arcuata. Longit. 3 millim., diam. 1. The spiral lirae upon the apical whorls are peculiar, and the apex itself is large in proportion to the size of the shell. |
