CAMBRIAN GEOLOGY AND PALEONTOLOGY
II
No. 3.—MIDDLE CAMBRIAN HOLOTHURIANS AND
MEDUSÆ
By CHARLES D. WALCOTT
(With Six Plates)
CONTENTS
| PAGE | ||||
| Introduction | 42 | |||
| Holothurians | 43 | |||
| Class Holothurioidea | 45 | |||
| Family Eldoniidæ, new family | 45 | |||
| Genus Eldonia, new genus | 45 | |||
| Eldonia ludwigi, new species | 46 | |||
| Muscles | 46 | |||
| Radial canals | 47 | |||
| Alimentary canal | 48 | |||
| Genital organs | 49 | |||
| Family Holothuriidæ | 52 | |||
| Genus Laggania, new genus | 52 | |||
| Laggania cambria, new species | 52 | |||
| Genus Louisella, new genus | 53 | |||
| Louisella pedunculata, new species | 53 | |||
| Family Synaptidæ | 53 | |||
| Genus Mackenzia, new genus | 54 | |||
| Mackenzia costalis, new species | 55 | |||
| Scyphomedusæ | 55 | |||
| Order Rhizostomæ | 55 | |||
| Family Undetermined | 55 | |||
| Genus Peytoia, new genus | 55 | |||
| Peytoia nathorsti, new species | 56 | |||
| Burgess shale. New name proposed in footnote | 51 | |||
PLATES
| Plate 8. | Peytoia nathorsti and Eldonia ludwigi | 58 |
| 9. | Eldonia ludwigi | 60 |
| 10. | Eldonia ludwigi | 62 |
| 11. | Eldonia ludwigi | 64 |
| 12. | Eldonia ludwigi | 66 |
| 13. | Laggania cambria, Mackenzia costalis, and Louisella pedunculata | 68 |
Smithsonian Miscellaneous Collections, Vol. 57, No. 3
41
