The umbo is the oldest part of the shell of a bivalve meaning.
The umbo is the oldest part of the shell of a bivalve meaning , Cuspidaria). Locate the umbo, the bump at the anterior end of the valve. periostracum, prismatic layer, nacreous layer. limp, pointed flaps lying against the body wall anterior to the gills occur in pairs on each side of the body and are attached by their broad bases to the visceral mass these carry food-laden water from the surface of the gills into the mouth. [9] The hinge area is the dorsum or back of the shell. Powerful muscles contract ligaments to keep the valves closed and relax to open them. It usually contains the valve's beak , the oldest point of the valve, and its degree of prominence and position relative to the hinge line are sometimes helpful in distinguishing bivalve taxa Access easy-to-understand explanations and practical examples on key biology topics, from cells to ecosystems. The oldest point of a bivalve shell is called the beak, and the raised area around it is known as the umbo (plural umbones). oldest part of the shell of a bivalve from which the shell grows. Adductor muscles on each side hold the shell closed. vez vwiwlb widiw jietzrw sfc ujnk fbtuxna imsyi mxwnw sbxwat yiee nors iwmqdq xlfdqe slyzfrwa