PLATE XI. 



Fig. Page - 



Proetus girvanensis, Nicholson and Etheridge. 74. 



1. Complete individual, x 2f. Thraive Gleu. Mrs. Gray's Collection. (Figured by 



Nicholson and Etheridge, 'Mon. Silur. Foss. Girvan,' pi. xii, fig. 10.) 



2. Head and part of thorax of partially enrolled individual, x 2\. Same locality and 



Collection. 

 2a. Side view of same specimen, x 2£. 



3. Complete individual (glabellar furrows not preserved), x 2k. Same locality and 



Collection. 



Proetus latifrons, M'Coy. 76. 



4. Imperfect head-shield, showing characters of glabella, x 3. Woodland Point. Mrs. 

 Gray's Collection. 



Proetus procerus, Nicholson and Etheridge. 77. 



5. Complete individual, x 3. Thraive Glen. Mrs. Gray's Collection. (Figured by Nicholson 



and Etheridge, 'Mon. Silur. Foss. Girvan,' pi. xii, fig. 11.) 



6. Nearly complete individual, with impression of hypostome seen in position, x 3. Same 



locality and Collection. 

 6a. Hypostome of same specimen, x 6. 



Proetus pseudolatifrons, sp. nov. 78. 



7. Imperfect head-shield, showing characters of glabella and broad border, x 2. Camregan 



Wood. Mrs. Gray's Collection. 



8. Pygidium, showing long conical axis, x 2. Same locality and Collection. 



9. Pygidium. x 2. Mulloch Hill. Mrs. Gray's Collection. 



Proetus Stokesi (Murchison). 79. 



10. Head-shield and part of thorax, x 4. Mulloch Hill. Mrs. Gray's Collection. 



11. Nearly perfect individual, x 3. Newlands. Mrs. Grav's Collection. 



Proetus. Cf. obconicus, Lindstrom. 81. 



12. Middle portion of head-shield, x 3. Woodland Point. Mrs. Gray's Collection. 



Proetus, sp. hid. hi. 



13. Imperfect head-shield, x 2. Craigens. Mrs. Gray's Collection. 



Arethusina konincki, Barrande! 



14. Head-shield, x 6. Balclatchie. Mrs. Gray's Collection. 



15. Pygidium. x K>. 



