Figure 27 in Phylogeny of cardiid bivalves (cockles and giant clams): revision of the Cardiinae and the importance of fossils in explaining disjunct biogeographical distributions

Figure 27. Hedecardium (Iheringicardium). A, ventral margin of right valve of H. (I) patagonicum (NHM PI TB4). White arrows indicate interspaces in which secondary radial threads are visible. Black arrows indicate primary radial threads on top of ribs. Scale bar = 10 mm. B, ventral margin of left valve of H. (I) philippii (NHM PI TB1). Arrow points to doubled rib. Scale in mm indicated on figure. C, external view of left valve of H. (I) ameghinoi (NHM L12549), hedeform shell shape. Arrows point to doubled ribs. Scale bar = 10 mm. D, closeup of ventral margin of same specimen as in C. Arrow points to