Homalozoa
Homalozoa is an obsolete extinct subphylum of Paleozoic era echinoderms, prehistoric marine invertebrates. They are also referred to as carpoids. Description The Homalozoa lacked the typical pentamer body form of other echinoderms, but all were sessile animals. Instead all Homalozoans were markedly asymmetric, and were extremely variable in forms. 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. Taxonomy Homalozoans were traditionally considered to be ...
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