NO. 12 SPENCE SHALE AND ITS FAUNA RESSER 27 



PAGE 



Olciioidcs brigluunciisis, new species 14 



Fig. 8. Cranidium. 



Fig. 9. Squeeze of pygidium. 



Locality 20x. 



Alokistocarclla spoicci, new species 18 



Fig. id. Holotype cranidium. 

 Koofcnia gracilis, new species 16 



Fig. II. Squeeze of cranidium. 



Fig. 12. Holotype pygidium. 



Locality 20x. 

 Zacaiithoidcs adjunct us. new species 9 



Fig. 13. Holotype. 



Fig. 14. Well-preserved pygidium. 

 Zacaiithoidcs gradatus, new species 9 



Fig. 15. Well-preserved pygidium. 



Fig. 16. Cranidium with right libragenc. 



Fig. 17. Holotype. 

 Zacanthoidcs idahocnsis, new species 9 



Fig. 18. Cranidium with occipital spine. 



Figs. 19, 20. Nearly complete individuals. 



Plate 4 



Olcnoidcs zvahsatchensis (Hall and Whitfield ) 14 



Fig. I. Squeeze of cranidium. 



Fig. 2. Pygidium. 



Locality 20x. 

 Olcnoidcs cvansi, new species 15 



Fig. 3. Cranidium 



Fig. 4. Holotype. 



Locality 55e. 

 Alohistocare septum, new species 17 



Fig. 5. Lidividual showing brim well. 



Fig. 6. Small cranidium. 



Fig. 7. Holotype. 

 Alokistocare idahocnse, new species 16 



Fig. 8. Libragene (X i-S). 



Fig. 9. Holotype. 

 Alokistocare spcnccnse, new species 16 



Fig. id. Holotype. 



Fig. II. Another individual showing pygidium and clianycd aspect 

 due to broken brim. 

 Chaiicia cbdoiiie Walcott 17 



Fig. 12. Cranidium. 



Fig. 13. Cranidium and displaced libragene. 



Fig. 14. A well-preserved specimen. 



