EXPLAXATION OF THE PLATES. Oo i 



PLATE XYIII. 



* The figures marked are left yalres, 



Unionidcs. 



Page 



1. "Unio littoralis, Drap. h AuA^ergne 433 



2. {Monocondylcsa) Paraguayanus, D'Orb. \. S. Americ?. 434 



3. Castalia ambigua, Lam. h. E. Amazon : 434 



4. Hyria sj-rmatopliora, Gronov. f . S. Ajnericaf 434 



5. *L-idina exotica, Lam. \. Africa, E. Nile 435 



6. ]\rycetopus soleniformis, D'Orb. i. S. America, E. Parana 435 



7. ^theria semiliinata, Lam. \. Senegal .• 435 



Chamidce. 



8. Cbama macropbylla, Cbemn. \, Antilles 437 



9. , left valve 437 



10. Diceras arietinnm. Lam. \. Coral Oolite, France 439 



il. left valve 439 



12. {Meqidenia) Lonsdalii, J. Sby. \. Neocomian, Spain 



—Brit , 439 



Hippuritidce. 



13. Caprotina striata, D'Orb. U. Grreensand, France 451 



14. left valve 451 



TridacnidcB. 



15. Tridacna squamosa, Chem. 1.. Bombay 452 



16. Hippopus maculatus, Lam. \. N. Australia 453 



Cardiadce (part). 



17. Lithocardium a\'iculare, Lam. \. Eocene, Paris 454 



Cyprinid<z (part). 



18. Cardilia semi-sulcata. Lam. Amboina 469 



19.*Megalodon cucullatus, J. Sby. \. Deronian, Eifel 469 



t The animal of Hijria has two ..iphonal orifices. 



