Severin, Kenneth P.&Lipps, Jere H. 1989 01 15: The weight‐volume relationship of the test ofAlveolinella quoyi:Implications for the taphonomy of large fusiform foraminifera.Lethaia, Vol. 22, pp. 1–12. Oslo. ISSN 0024–1164.Alveolinella quoyi, the largest living fusiform foraminifer, can be used to infer the paleobiology of extinct fusulinids and alveolinids. We measured test plus organic material weight, test weight, and test volume forA. quoyi, allowing the calculation of test density under various conditions. Tests have an average of 43% chamber space, and an average density of 1.5 gcm‐3. Living individuals can only fill an average of 39% of their chamber space with protoplasm. If they fill the remaining space with sea water, average effective test density is 0.953 gcm‐3, if the space is filled with a gas the density is 0.671 gcm‐3. Living individuals can withstand current velocities of 3–4 m sec‐1, velocities greater than commonly occur inA. quoyi'shabitat. Dead tests have lower effective densities than many carbonate sedimentary particles (0.508 g cm‐3if the chamber space is gas filled, 0.953 g cm‐3if it is sea water filled), making their settling velocities slow relative to similarly shaped and sized particles. Their large size and high traction velocities (>0.2m sec‐1) makes them unaffected by gentle currents which can remove 100–200 μ sized particles from the sediment. Their low settling velocity will tend to concentrateA. quoyitests during subsequent resuspension, creating a layer of tests near the sediment‐water interface. Concentrations of extinct fusiform foraminifera may have formed in a similar manner. □Lorger foraminifera, test weight, test vol