Cyclos tom a (siklos tom a)

[NL., fem. sing. tomous.] 1. The typical genus of the family Cy clostomida: so called from the circular aperture of the shell. Very different limits have been given to it, the old writers including not only all the true Cyclos to midæ, but also the Cyclophoridæ and Pomatiide, while by most modern writers it is limited to those with a calcareous paucispiral operculum flattened and having an eccentric nucleus. The species are numerous; they live in damp places. C. elegans is an example. See cut under Cyclos to mid a. Also Cyclos tom us. neut. pl.) of cyclos tom us: see cyclos 2. [Used as a plural.] The cyclostomatous vertebrates, or myzonts.