EXPLANATION OF PLATES. 443 
FIGURE. PAGE, 
2. Triquetraavicularis, Lam. Brazil, . : : . 243 
3, 4. Prisodon ambigua, Lam. Brazil, , . 243 
5. Iridina (Leila) Blainvilliana, Lea. So. America, . 243 
6. Aitheria Cailliaudi, Fer. River Nile, . : : . 244 
7. Bartlettia Stefanensis, Moric. Amazon River, . . 245 
8. Iridina (Spatha) rubens, Lam. River Nile, 1 . 243 
PLATE 125. 
8, 9. Iridina (Haplotherus) capax, Conr. Pebas apap, 
Upper Amazon, . , . 243 
10. Anthracosia Lottneri, Ludw. Carboniferous, f . 236 
11. Mycetopus soleniformis, dOrb. So. America, : . 244 
12, 13. Solenaia emarginatus, Lea. Siam, : ; . 244 
14, 15. Muileria Guaduasiana, d’Orb. So. America, . . 244 
16, 17. Arconaia contorta, Lea. China, . : . 243 
18. Trigonia pectinata, Lam. Australia. From a a specimen 
in alcohol; the gills slightly curled and contracted, 
they should terminate near the margin, between the 
arrows which indicate the inhalent and exhalent cur- 
rents; a, a’, adductors; A 1, ligament; ¢, t’, dental 
sockets; 0, mouth; / ¢, labial tentacles or palpi; D; 
pallial line ; m, margin : J, foot; v, cloaca, : . 245 
9: Trigonia navis, Lam. Liassic ; Alsace, , : . 246 
20. Trigonia costata, Park. 4. Oolite ; Britain, : . 246 
21. Trigonia longa, Agass. Neocomian ; ; Neuchatel, . 246 
22. Trigonia Parkinsoni, Agass. Portlandian ; Besancon, 246 
23. Trigonia scabra, Lam. Cretaceous; France, ; . 246 
24. Curtonotus elongatus, Salter. Devonian; England, . 247 
25. Paleoneilo Bedfordensis, Meek. (Cast.) Carb.; Ohio, 250 
26. Verticordia cardiformis, Wood. Crag, Suffolk, Eng., 197 
PLATE 126. 
27. Nucula obliqua, Lam. Australia, : 2 ; . 248 
28. Nucula (Acila) divaricata, Hinds. China Sea, . . 248 
29. Nucula ( Acila) ornatissima, d’Orb. Cret.; Kur., . 248 
30. Ctenodonta Pectunculoides, Hall. L. Silur.; Cincin- 
nati, Ohio, . ; 5 : ; . 260 
31. Leda pernula, Muller. Boreal Seas, ‘ , . 248 
32. Leda (Adrana) Sowerbyana, d’Orb. Xipixapi, ; . 249 
33. Yoldia myalis, Couth. United States, : : . 249 
34. Yoldia (Malletia) Chilensis, Desm. Valparaiso, . 249 
35. Yoldia (Neilo) Cumingii, A. Ad. (— Australis, Quoy). 
New Zealand, . 250 
36. Yoldia | Nucularia) papyria, ‘Conr. Oret. ; N. Jersey, 250 
37, 38. Glyptarca primeva, Hicks. Silurian; Wales, . 255 
39. Arca Nox, Linn. Mediterranean, : : : . 252 
