98 MOLLUSCA IN THE MaYA LoWLANDS 



Pl. 18 — CARDIIDAE 



a. Trachycardium isocardia Linne (M-313), aa (4150). 



b. Trachycardium mtiricatum Linne (M— 220), bb (7203). 



c. Trachycardium magnum Linne (Q-502), cc (4985). 



d. Dinocardium robustum vanhyningi Clench and Smith (M-562-A), dd (7296). 



(Actual size) 



