The Cambridge natural history . he number ofmarginals is said to vary from none (in T. acicida) to* three (), but the fact wants confirmation. Solarium is anaberrant form, possessing simply a number of. long uncini, whichrecall those of Conus or Pleurotoma, and is therefore hard toclassify; the allied Torinia has a radula which appears alliedto Ovula or Pedicularia. In Triforis the teeth are identicalthroughout, very small, about 27 in a row, tricuspid on a squarebase, cusps short. The normal formula of the Taenioglossa is ; inLamellaria, ; in Triforis, , or t
The Cambridge natural history . he number ofmarginals is said to vary from none (in T. acicida) to* three (), but the fact wants confirmation. Solarium is anaberrant form, possessing simply a number of. long uncini, whichrecall those of Conus or Pleurotoma, and is therefore hard toclassify; the allied Torinia has a radula which appears alliedto Ovula or Pedicularia. In Triforis the teeth are identicalthroughout, very small, about 27 in a row, tricuspid on a squarebase, cusps short. The normal formula of the Taenioglossa is ; inLamellaria, ; in Triforis, , or thereabouts. {d) Pteiioglossa.—Thissection consists of twofamilies only, which cer-tainly appear remarkablydissimilar in general habitsand appearance, viz., thelanthinidae and Scalarii- ^ 2Z^^^-^^^-^-^^^--^^ ^^^ ^?^ ^^^ probability ...^--^,—^ ,<r:_*---::j k—^.---^ their approximation is only provisional. Theradula, which in lanthinais very large, and inScalaria very small, possesses an indefinite number of long hooked. Fig. 128.—Portion of the raclnla of lanthinacommunis Lam. x 40. RADULA OF THE PTENOGLOSSA, ETC. 225 teeth, of which the outermost are the largest. The centraltooth, if present (it does not occur in lanthinci), is the smallestin the series, and thus recalls the arrangement in some of tliecarnivorous Pulmonata (p. 232). In lantldna the radula isformed of two large divisions, with a gap between them downthe middle. The formula is or according as the centraltooth in Scalaria is or is not reckoned to exist. (e) Gymnoglossa.—In the absence of both jaw and radida it isnot easy to classify the two families (Eulimidae and Pyrami-dellidae) which are grouped under this section. Fischer regardsthem as modified Ptenoglossa; one would think it more naturalto approximate them to the Taenioglossa.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
