ILLUSTRATIONS. 



Plates I-CIV Part II 



Figure 1. Billingsella plicatella 299 



2. Dalmanella subequata 299 



3. Kutorgina cingulata 299 



4. Obolus apollinis 299 



5. Billingsella coloradoensis 299 



6. Nisusia festinata 299 



7. Eoorthis remnicha 299 



8. Kutorgina cingulata ' 299 



9. Dalmanella multisecta 299 



10. Dalmanella parva 299 



11. Syntrophia lateralis 299 



12. Plectorthis plicatella 299 



13. Huenella abnormis 299 



14. Obolella crassa 299 



15. Obolus apollinis 299 



16. Dicellomus politus 314 



17. Diagram illustrating known distribution of families in Cambrian strata 316 



18. Schematic diagram of evolution of Cambrian Bracliiopoda 317 



19. Rustella ? major 328 



20. Micromitra haydeni 338 



21. Micromitra scotica .■ 340 



22. Micromitra sculptilis eudlichi - '. 342 



23. Micromitra zenobia 342 



24. Micromitra (Paterina) labradorica utahensis 350 



25. Micromitra (Paterina) major 351 



26. Micromitra (Paterina) stuarti 355 



27. Micromitra (Paterina) superba 355 



28. Micromitra (Paterina) undosa 356 



29. Micromitra (Paterina) wapta 357 



30. Micromitra (Paterina) williardi 358 



31. Micromitra (IpMdella) louise 359 



32. Micromitra (Iphidella) pannula 362 



33. Volborthia recurva 366 



34. Interiors of valves of Obolus apollinis quenstedti and Lingula anatina 374 



35. Obolus dolatus 390 



36. Obolus membranaceus 403 



37. Obolus parvus 408 



38. Obolus smithi 416 



39. Obolus wortheni 421 



40. Obolus (Westonia) dartoni 455 



41. Obolus (Westonia) wasatchensis 467 



i2. Lingulella clarkei 486 



43. Lingulella isse 510 



44. Lingulella triparilis . . .'. 537 



45. Lingulella zeus 54I 



46. Lingulella (Lingulepis) acuminata sequens 55I 



47. Neobolus warthi 567 



48. Dicellomus pectenoides 575 



49. Dicellomus politus , 576 



50. Kutorgina cingulata 581 



51. Obolella atlantica 59O 



52. Obolella groomi 596 



9 



