part of start stage end stage multi-tissue structure maxillary barbel blood sinus central chamber of the maxillary blood sinus 2014-10-24T02:27:58Z zebrafish_anatomy yvonne ZFA:0007076 Is a multi-tissue structure that is located outside the maxillary barbel proper and is positioned on the lateral surface of the maxilla, medially attached to the lateral surface of the maxillary bone and is laterally is attached to a hemispheric capsule of dense connective tissue of the distal bulb. It connects with the smaller accessory chamber through a slight isthmus. It has a smooth muscle tunic from which extend luminally projecting muscular septa. juvenile:days 30-44 adult