The Cambridge natural history . and laterals, the same highly magnified. 140, E); (^) central tooth small and narrow^ laterals bicuspid,marginals as in Helix {Amastrcc and Carelia). Succineidae : Central and laterals helicidan, Iji- or tricuspid ona quadrate plate, marginals denticulate on a narrow base; jawwith an accessory oblong plate. JcMellidae : Central tooth very small, laterals and marginalslike Achatinellidae («). Vagimdidar : Central, laterals, and marginals unicuspidthroughout, on same plan. Onchidiidac : Eows oblique at the centre, straight near the RADULA OF PULMONATA 235 edges; c
The Cambridge natural history . and laterals, the same highly magnified. 140, E); (^) central tooth small and narrow^ laterals bicuspid,marginals as in Helix {Amastrcc and Carelia). Succineidae : Central and laterals helicidan, Iji- or tricuspid ona quadrate plate, marginals denticulate on a narrow base; jawwith an accessory oblong plate. JcMellidae : Central tooth very small, laterals and marginalslike Achatinellidae («). Vagimdidar : Central, laterals, and marginals unicuspidthroughout, on same plan. Onchidiidac : Eows oblique at the centre, straight near the RADULA OF PULMONATA 235 edges; central strong, tricuspid; laterals and marginals verylong, falciform, arched, unicuspid. Aurictdidae : Teeth very small; central narrow, tricuspid onrather a broad liase ; laterals and marginals ol)scurely tricuspid ona Imse like Succinea. Limnaeidac: Jaw composed of one upper and two lateralpieces ; central and lateral teeth reseml>ling those of Helicidae ;marginals much pectinated and serriform (Fig. 141. A). In ^^^^mmwp. Aw \L^^ Fig. 141.^—Portions of the radiila ofA, Limnaea stagnalis L., -with thecentral tooth and two first laterals,and two of the marginals, veryhighly magnified ; B, Aticylvsfluviatilis Miill., with two of themarginals very highly magnified ;C, Physa fontinalis L., with cen-tral tooth and two of the marginalsvery highly magnified. Ancylvs proper the teeth are of a very different type, basenarrow, head rather blunt, with no sharp cusps, teeth similarthroughout, except that the marginals become somewhat pec-tinated (Fig. 141, B); another type more resembles Limnaea. Physidae: Jaw simple, but with a fibrous growth at itsupper edge, wliich may represent an accessory plate; radulawith very oblique rows, central tooth denticulate, laterals and 236 KADULA OF SCAPHOPODA AND CEPHALOPODA marginals serriform, comb-like, with a wing-like appendage atthe superior outer edge (Fig. 141, C). Chilinidae : Central tooth small, cusped on an excavated tri-angular base,
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
