720 . CLASSIS XII. 



latere antico breviori. Gardo dentibus duobus in valva dextra, 

 fbveola intermedia dentem unicum sinistrae excipiente. Dentes 

 laterales duo. Ligamentum duplex; externum parvum, intermim 

 apophysi cocblearilbrmi recejjtum. Animal trarbeis duabus tlis- 

 cretis, longis. 



Sp. Syndosmya alba, Amphidcsma BoysiiLAH. ; Desh., Conchyl. 

 PI. 8. lig. 6-8 etc. 



Trigonclla da Costa, Desh. (Mactrae spec. Gmel. , Ma- 

 ctrae subgenus Cuv., Lutrariae sp. Lam.). Testa orbiculato- 

 trigona, plana, subaequilatera , latere antico breviori, rotundato, 

 poslico subhiante. Cardo angustus, dentibus parvis duobus in 

 valva dextra, unico in sinistra ; Fovea triangularis ligamentum in- 

 termim reeipiens. Ligamentum externum parvum. Animal tra- 

 cbeis longis, gräcilibus, discretis, admodum inaequalibus. 



Sp. Tiigonella plana Lo\i : :n, Mactra piperata Gmel. , Lutra- 

 lia compressa Lam.; Ri.ainy., Maluc. PI. 77. flg. 2.; Raster, iVa- 

 tuurk. Uitsp. II. Tab. VIII. fig. 5 — 7.; diese Art halt sich tief im Sande 

 an Meeresküsten auf und kommt auch fossil in der Cragformalion vor. 



Cumingia So werbt. 



Sp. Cumingia lellinoidcs Desh., Conchyl. PI. 8. lig. 9 — 11.; spe- 

 cies omnes exoticae. 



Mesodesma Desh. Testa transversa, latere antico lon- 

 giori, crassa, clausa. Ligamentum nonnisi irilernum, fovea an- 

 gusta, profunda reeeptum. Cardo deute uno duobusvc sub apice, 

 duobusque lateialibus. Animal tracbeis duabus discretis (Pe- 

 ronaea Doli). 



Sp. Mesodesma Quoyi Desh., Conchyl. PI. 10. lig. 13. 14. — Me- 

 sodesma Cornea Desh., A m p h i d e s in a donacilla Lam.; Poli, 

 Tcstac. ulr. Sicil. Tab. XIX. fig. 8 — 11. (Mactra Cornea, habilus 

 fere Donacis), 



Gnatbodon Gray, Rangia Desmoulins. 



Sp. Gnalhodon euneatus Gray; Desh., Conchyl. PI. 10. fig. 9 — 12. 

 Cr. Rang, Nunc. Ann. du Mus. III. 1834. p. 217-230. PI. 12. Diese 

 Art lebt im Brackwasser des grossen Sce's Pontebartrain in Louisiana. 



Anatinclla Sow. 



Sp. Analineila Sibbaldji Sow., Mya Ciiemn., Conchyl. Tah. 3. fig. 

 17. 18. ; Desh., Conchyl. PI. 8. fig. 4. 5. 



Mactra L. Testa transversa, inaequilatera , utrinque sub- 

 bians. Processus excavatus sub apieibus in cardine, ligamen- 

 tum internum reeipiens; dens cardinalis bifidus aut furcatus ante 





