Fig. 4

Shell microstructure of A. lobifera specimens that lived first in natural environments ((A), (C)) and, for the secretion of the last few chambers, were transferred into water contaminated with either Cd²⁺ or Pb²⁺ ((B), (D)). (A) to (D): EBSD scans showing crystal orientation. Yellow rectangles in inserts in (B), (D) indicate the positions of EBSD scans shown in (B), (D). (B) shows the shell wall of the last chamber, (D) shows the shell wall of the last but fifth chamber. There is no marked difference in microstructure between shell sections secreted under natural and under Cd²⁺- or Pb²⁺-poisoned conditions.