Homalozoaとは 意味・読み方・使い方

The Homalozoa are extinct, Paleozoic echinoderms that lacked the typical pentamer body form. Instead all homalozoans were markedly asymmetric. Homalozoans are extremely variable in forms, but they all were sessile animals. The body (theca) was covered with calcite plates with a number of openings. Their form is in some cases so unusual that it is unclear which openings are to be considered as mouth and anus. Many of them were stalked, similar to sea lilies (crinoids), but often their bodies were bent over, so that the mouth and anus projected forwards rather than upwards. Some forms, especially stylophorans, rested flat on the sea floor. In some forms the single ray (brachiole or aulacophore) possessed an ambulacral groove. It has been claimed that some forms possessed gills and gill slits.