from The Century Dictionary.
- noun The typical genus of Planorbinæ.
from the GNU version of the Collaborative International Dictionary of English.
- noun (Zoöl.) Any fresh-water air-breathing mollusk belonging to Planorbis and other allied genera, having shells of a discoidal form.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun zoology Any of the
freshwaterair-breathing mollusksbelonging to Planorbis and allied genera, having shellsof a discoidalform.
from Wiktionary, Creative Commons Attribution/Share-Alike License
But P. planorbis is characterized by a keel around the periphery of the shell, which the specimens from Karagöl are lacking.
Lacking a microscope, we initially thought they were Planorbis planorbis, a species recorded from Turkey before.
Of the many varieties, one, the largest, the horn-coloured _planorbis_, emits a purple dye.