| 释义 |
‖ Planorbis Zool.|pləˈnɔːbɪs|
[mod.L., f. plān-us plane a. + orbis orb.]
A genus of freshwater snails (pond-snails), characterized by a flat rounded spiral shell.
1833Lyell Princ. Geol. III. 238 We find in the marls and limestones the shells of the Planorbis, and other lacustrine testacea. 1876Beneden's Anim. Parasites 38 A gasteropod mollusc, similar to a Planorbis, which lives as a messmate in the body of an annelid.
Comb.1878Bell Gegenbaur's Comp. Anat. 81 The planorbis-like shells of the Milliolidæ represent the simplest condition of these forms.
Hence plaˈnorbiform, plaˈnorboid adjs., resembling, or having the form of a Planorbis; of a flat rounded spiral shape; plaˈnorbine a., belonging to, or having the characters of, the subfamily Planorbīnæ, of which Planorbis is the typical genus; plaˈnorbite, a fossil shell belonging or allied to this genus; plaˈnorbuline a., of or belonging to Planorbulīna, a genus of Foraminifera having shells of a planorboid form.
1856Woodward Mollusca iii. 398 The Achatinellæ are elongated..and the Helices planorboid and multispiral. 1879Carpenter in Encycl. Brit. IX. 380/1 Remarkable modifications of the planorbuline type. 1895Cambr. Nat. Hist. III. 413 Shell very small, planorbiform. |