18 MANUAL OF THE MOLLTJSCA. 



PLATE XVIII. 



* The figures marked are left valves. 

 Unionidce, 



PAGE 



1. Unio litoralis, Drap. \. Auvergne 274 



2. (Nonocondylad) Paraguayans, D'Orb. \. S.America... 274 



3. Castalia ambigua, Lam. \. R. Amazon 275 



4. Hyria syrmatophora, Gronov. \. S. Americaf 274 



5. *Iridina exotica, Lam. \. Africa, R. Nile 275 



6. Mycetopus soleniformis, D'Orb. . S. America, ft. Parana 275 



7. ^Etheria semilunata, Lam. \. Senegal 275 



Chamida. 



8. Chama macrophylla, Chemn. \. Antilles 276 



9. left valve 



10. Diceras arietinnm, Lam. ^. Coral-Oolite, France ., 278 



11. left valve 278* 



12. (Requienia) Lonsdalii, J. Sby. \. Neocomian, Spain Brit. 279 



] 3, Caprotina striata, D'Orb. U. Green-sand, France 289 



14. left valve 289 



Tiidacnida. 



15. Tridacna squamosa, Chemn. . Bombay 290 



16. Hippopus maculatus, Lam. \. N.Australia ., 290 



Cardiadce (part). 



17. Lithocardium aviculare, Lam. . Eocene, Paris 291 



Cyprinidfe (part). 



18. Cardilia semi-sulcata, Lam. Amboina 301 



19.*Megalodon cucullatus, J. Sby. \. Devonian, Eifel 301 



t The animal of Hyria has two siphon al orifices. 



