PLATE XVIII. 



<"lQ. PAGE. 



Calymene blumenbachi, var. nov. drummuckensis. 135. 



1. Head-shield. Nat. size. Thraive Glen (Starfish Bed). Mrs. Gray's Collection. 



2. Complete individual. Nat. size. Same locality and Collection. 



3. Head-shield, x 1|. Same locality and Collection. 



4. Pygidium. Nat. size. Same locality and Collection. 



Cheirurus gelasinosus (Portlock). 140. 



5. Glabella. Nat. size. Craighead. Mrs. Gray's Collection. 



6. Some thoracic segments. Nat. size. Same locality and Collection. 



Cheirurus gelasinosus, var. ?. 141. 



7. Glabella, x 21 . Balclatchie. Museum of Practical Geology. 



Cheirurus (Cyrtometopus) octolobatus (M'Coy). 141. 



8. Part of thorax with pygidium attached, x 2. Thraive Glen. Mrs. Gray's Collection. 

 8n. Three anterior thoracic segments of same specimen. X 2. 



9. Head-shield. x 11. Same locality and Collection. 



10. Head-shield. Nat. size. Same locality and Collection. 



11. Pygidium. x 21. Same locality and Collection. 



Cheirurus (Nieszkowskia) unicus (Wyville Thomson). 142. 



12. Nearly complete individual, x 2£. Balclatchie. Mrs. Gray's Collection. 



13. Glabella,. x 21. Same locality and Collection. 



1 k < >ut line drawing of side view of head-shield, to sho\n downward bending of same. 



15. Nearly complete individual, showing pygidium. x 21. Same locality and Collection. 



( Figured by Nicholson and Etheridge, op. cih, fasc. i, pi. viii, fig. lt». ) 



16. Pygidium. x •![.. Same locality and Collection. 



Cheirurus (Sphaerocoryphe) thomsoni, sp. nov. 146. 



17. Imperfect individual, showing head-shield and pygidium. x 2. Thraive Glen. Mrs. 



( l-ray's < !ollection. 

 17r Outline restoration of thoracic pleura of same, x 3. 



