EXPLANATION OF PLATES. 29/ 



FIG. 



Fam. Cardiacea. 



121. Venericardia, recent species, resembling V. planicostata, Lam. 



122. Cardium Dionseum. Cardissa, Sw. Hemicardium, Nonnull. 



123. angulatum. 



123*. Greenlandicum. Aphrodita, Lea, Acardo, Sw. 



123**. hemicardium. Gen. Hemicardum. 



124. Cardita calyculata. 



125. Cypricardia angulata. 



126. Isocardia Moltkiana. 



127. Megalodon cucullatus, (from Sow. Min. Con.) 



128. Hippagus Isocardioides, (from Lea.) 



129. Hippopodium ponderosum, (from Sow. Min. Con.) 



130. Pachymya gigas, (from Sow. Min. Con.) 



Fam. Arcacea. 



131. Area antiquata. 



132. Bysso-arca Nose. 



133. Cucullsea auriculifera, (from Sowerby's Genera.) 



134. Pectunculus pilosus. 



1 35. Myopara costata, (from Lea.) 



136. Crenella. 



137. Nucula margaritacea, three views. 



138. Solenella Norrissii. 



Fam. Trigonacea. 



139. Trigonia pectinata. 



140. Castalia ambigua. Tetraplodon pectinatus, Spix. 



Fam. Nayades. 



141. Alasmodon complanatus, Say. Margaritana, Schum. 



142. Dipsas plicatus, Leach. Cristaria, Schum. 



143. Hyria corrugata, Lam. Paxyodon, Schum. Triplodon. 



144. Syrmatophora, Sow. Prisodon, Schum. Diplodon, Spix. 



145. Unio littoralis, Lam. Mysca ovata, Turton. 



147. Alatus. Symphynota, Lea. 



148. Atratus, Lam. Naia, Sw. 



