triaene with three clads and in addition to the normal rhabd a second rhabd in the opposing position. If the triaene is a dichotriaene the spicule is called dichomesotriaene.
Alternative forms for centrotriaene : centrotriaenes, dichomesotriaene, dichomesotriaenes, mesotriaene, mesotriaenes.
SEM from Maldonado, 1992