"Since the taxa which have been included in the Bathymetrinae and Zenometrinae include all intermediate arrangements of the cirrus sockets and shapes of the centrodorsal from completely irregular on a low hemispherical ossicle in Bathymetra to well-marked vertical columns on a conical or columnar centrodorsal in Zenometra, I consider that these two subfamilies should be merged." (AM Clark, 1980, footnote p. 199). Although AM Clark wrote this before Messing & White (2001) removed three of the genera with cirri in distinct columns, including Zenometra, to Zenometridae, her observation still holds for the remaining genera. The subfamily is likely polyphyletic.
Clark AM (1980) Crinoidea collected by the Meteor and Discovery in the NE Atlantic. Bulletin of the British Museum of Natural History (Zoology) 38(4):187-210.