EXPLANATION OF PLATES. 297 



FIG. 



Fam. Cardiacea. 



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



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



123. angulatum. 



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



123**. hemicardium. Gen. Hemicardum. 



124. Cardita caly culata . 



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 Noee. 



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

 ] 34. Pectunculus pilosus. 



135. Myopara costata, (from Lea.) 



136. Crenella. 



137. Nucula margaritacea, three views. 



138. Solenella Norrissii. 



Fain. 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. 



