A treatise on malacology; or, Shells and shell fish . * Ency. Meth. pi. 459. fig. 7- 188 SHELLS AND SHELL-FISH. PART I. for this fold on the pillar, it could not be distinguishedfrom a Limnceus. The fifth and last type is Ancylus,composed of the freshwater limpets (^fig. 32.), not even mentioned by Cuvier, but con-stituting one of the most re-markable divisions of the wholegroup. (173.) The five genera,placed opposite to those of thegenera of AchatincB, and thesub-families of the Helicidce,will be found to represent eachother thus: —. Generaof the Planorbis. Ancylus. Pototnophila.
A treatise on malacology; or, Shells and shell fish . * Ency. Meth. pi. 459. fig. 7- 188 SHELLS AND SHELL-FISH. PART I. for this fold on the pillar, it could not be distinguishedfrom a Limnceus. The fifth and last type is Ancylus,composed of the freshwater limpets (^fig. 32.), not even mentioned by Cuvier, but con-stituting one of the most re-markable divisions of the wholegroup. (173.) The five genera,placed opposite to those of thegenera of AchatincB, and thesub-families of the Helicidce,will be found to represent eachother thus: —. Generaof the Planorbis. Ancylus. Pototnophila. Physa. Limrueus. Analogies of the Limnacin^. Analogies. Sub-families Generaof the of the Helicidce. Achatina. r Shell depressed disk-like; | Lucernin^. aperture round. 3 f Shell fragile, much smaller 7 Lt^.^^iNiE. Helicina.(_ than the animal. y } Shell thin ; aperture large ;) Lj^n^cin^. pillar plaited. 3 (•Outer lip thin; last whorl 7 ^^„^^,^^i contracted. 3 Outer lip reflected; basal Achatina. { whorl very large. i« ELiciN.£. Bulimus. The general analogies of the whole group may befirst slightly touched upon. The LimnacincE occupythat station in the circle of the Helicidce, which corre-sponds to that of the Cephalopoda in the great tribe ofTestacea. Hence they are all aquatic animals ; and ifthis analogy is correct, it follows that Planoi-his is thetypical group, because, in their flat discoid shells, theyperfectly agree with the equally depressed and convo-luted Nautili. We have seen, also, th
Size: 1463px × 1708px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, booksubjectmollusks, bookyear184
