286 Bulletin 39 458 



Page 



6. Plicatula marginata Say, Water Cay, the lower or attached 



valve, enlarged about 2 >^ time.... 208 



7. Plicatula marginata Sa)', Water Cay, the lower or attached 



valve, enlarged about 2>^ times . 208 



8. Echinochama antiquata Dall, Rio Blanco 218 



9. Pteria inornata Gabb, Red Cliff Creek, natural size 195 



10. Limasa solida Dall, Red Cliff Creek, height 2.5 mm 209 



11. Chama congregata Conrad, Red Cliff Creek, enlarged about 



twice 218 



12. Corbula oropendula, n. sp., Banana River, length 6.5 mm 267 



13. Corbnla oropendula, n. sp., Banana River, same valve but 



less magnified, length 6.5 mm 



14. Corbula oropendula, n. sp. , same locality, right valve, 6.5 



mm. 



15. Corbula cf. vieta Guppy, Banana River, right valve, length 



6.25 mm 266 



16. Corbula cf. vieta Guppy, Banana River, left valve, length 



6.25 mm. 



17. Leda Dalliana, n. sp., Port Ivimon, length 10.50 mm 175 



18. Mesodesma costaricensis, n. sp. , Banana River, length 22 



mm 265 



19. Nucula orbicella, n. sp., Port Ivimon, length 9.5 mm 171 



20. Nucula orbicella, n. sp., Port L,imon, length 11 mm. 



21-22. Yoldia bocasensis, n. sp., Bocas del Toro, length 9.5 mm... 176 



23. Mulinia lateralis Say, variety sauryensis, n. var.. Saury 



Creek, about natural size 265 



24. Mulinia lateralis Say, variety saurj'ensis, n. van, Saury 



Creek, about natural size. 



25. Corbula viminea Guppy, Middle Creek, length 15 mm 270 



26-27. Corbula oropendula, n. sp.. Saury Creek, length 9 mm 267 



PLATE 29 (32) 



Fig. I. Semele Isevis Sowerby, variety costaricensis, n. var. , Hill 3, 



Banana River, length 72 mm 258 



2. Semele Claytoni Maury, Hotel Creek, natural size 359 



3. Metis barba, n. sp. , Rio Betey (type), right valve, length 



48 mm 255 



4. Metis barba, n. sp., Rio Betey (t3''pe), left valve, length 



48 mm. 



