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Show 266 MR. E. A. SMITH ON THE [Apr.], longit. totius \ cequans; labrum leviter incrassatum, intus den-ticulatum; columella triplicata. Longit. 5 millim., diam 2\. This species at first sight looks very like the shell previously described as Pleurotoma multigranosa, but, of course, is perfectly distinct. It is remarkable for its small size, the minutely beaded ribs, the dark apex, and the style of coloration. Allied to M. albo-cincta, C. B. Adams. MITRA (THALA) PLEUROTOMOIDES. (Plate XXIII. fig. 10.) Testa parva, breviter fusiformis, albida, interdum luteo-tincta; anfractus sex, duo supremi Iceves, superne acute carinati, plani, quasi truncati, cceteri convexiusculi, costis longitudinalibus circiter 16, lirisque transversis (in anfr. penult. 5-6, in ultimo 18-20) granose clathrati; apertura parva, angusta, longit. totius ^ adcequans ; labrum leviter incrassatum, denticulis circiter sex intus munitum, postice distincte sinuatum; columella rec-tiuscula, leviter obliqua, in medio plicis duobus instructa, tenui superne labro juncto induta. Longit. 5 millim., diam. 2. This species is remarkable for the peculiar truncate apex, the Pleurotomoid labral sinus, and the columellar plaits being two only in number. Fischer (Man. Conch, p. 612) has pointed out that Mitras of the group Thala have much affinity with the shells of Clathurella and Mangilia. I might point out that one species, Thala solida, was described by Reeve1 as belonging to the latter genus, and another, Thala todilla, was originally published by Mighels" as a species of Pleurotoma. It therefore still remains doubtful to which family, Pleurotomidce or Mitridce, this group should be referred. MARGINELLA (VOLVARIA) CINEREA, Jousseaume. The type of this species, M. semen of Reeve, not of Lea, described by Reeve (Conch. Icon. pi. xxvi. fig. 145), is now in the Museum, having been presented by Mrs. Lombe Taylor after the death of her husband. It is incorrectly said by Reeve to have four plaits on the columella, for on careful examination only three are discernible, nor is this number exceeded in any of the specimens, nearly twenty in number, from St. Helena. Reeve's figure does not accurately represent the form of the spire, and the sutural line is too low down. No locality has previously been quoted for it. MARGINELLA (VOLVARIA) CONSANGUINEA. (Plate XXIII. fig. 11.) Testa minuta, ovata, alba, nitida, pellucida ; anfractus 3-4 ,- spira brevissima, obtusissime conica; anfr. ultimus elongate ovatus, medio labri levissime constrictus ; apertura angustissima; labrum paulo incrassatum, inflexum, arcuatum, intus laive, 1 Conch. Icon. (Mangelia), sp. 64. 2 Proc. Bost. Soc. Nat. Hist. 1845, vol. i. p. 24. |
