PLATE VII. 



Fig. Page. 



Asaphus (Isotelus) gigas, De Kay. 45. 



1. Head-shield. X 2. Ardmillan. Mrs. Gray's Collection. 



Asaphus (Isotelus) instabilis, sp. nov. 46. 



2. Pygidiura. X H- Dow Hill. Mrs. Gray's Collection. 



3. Imperfect head-sliield. X H. Balclatchie. Same Collection. 



4. Ditto. X 2. Dow Hill. Same Collection. 



5. Pygidium. x 2. Dow Hill. Sedgwick Museum. 



6. Head-shield and portion of thorax of young individual. X 2. Dow 



Hill. Mrs. Gray's Collection. 



7. Pygidium and portion of thorax. X 2. Same locality and Collection. 



8. Hypostome. X 2^. Same locality and Collection. 



Asaphus, sp. 49. 



9. Head-shield. X 1^. Minuntion. Mrs. Gray's Collection. 



Stygina latifrons (Portlock). 50. 



10. Pygidium. X 2. Shalloch Mill. Mrs. Gray's Collection. 



Cyclopyge armata (Barrande). 51. 



11. Glabella, showing ornamentation and furrows. X 2. Whitehouse Bay. 



Mrs. Gray's Collection. 



12. Glabella, showing furrows. X 2. Same locality and Collection. 



1 :'>. Epistome and portion of eyes. X 3. Same locality and Collection. 

 14. Eye and free cheek. X 3. Same locality and Collection. 



