79 
Explanation of Plate VII. 
Fig. 1. Tetr odium halysitoides, Raymond. Weathered vertical section of a corallum, 
showing the corallites in section, and also the rod-like supports which 
extend across the spaces between the lamellse of cells. 
“ 2. Bathyurus johnstoni, Raymond. A thorax and pygidium. Natural size. 
“ 3. The same species. An imperfect cranidium, showing the large and numerous 
pustules. Natural size. 
“ 4. Bathyurus acutus, Raymond. A perfect pygidium. Natural size. 
“ 5. Bathyurus angelini, Billings. An hypostoma from the Beekmantown at Gren- 
ville, Que. Twice natural size. 
u 6. Bathyurus sp. A form with a wide depressed border on the pygidium. In- 
termediate between B. extant ansd B. superbus. About natural size. 
“ 7. Bathyurus ingalli, Raymond. A cranidium. Natural size. 
“ 8. Petigurus nero, (Billings). One of the cotypes, to show how the pygidium 
differs from that of Bathyurus. Natural size, 
“ 9. Hystricurus conicus, (Billings). The type, to show how the glabella differs 
from that of Bathyurus. Natural size. 
“ 10. Goniurus perspicator, (Billings). A pygidium. 3i times natural size. 
“ 11. Goniurus elongatus, Raymond. J larger than natural size. 
“ 12. The same species. Natural size. 
“ 13. Haploconw smithi, (Billings). A small, entire specimen, 4 times natural 
size. 
“ 14. The. same specimen, viewed from the side. 4 times natural size. 
“ 15. Lloydia bituberculatus, (Billings), Cranidium of the holotype. Natural size. 
“ 16, Lloydia saffordi, (Billings). A pygidium. Natural size, 
“ 17. Leiostegium quadratum, (Billings.) A cranidium and pygidium. Natural 
size. 
** 18. Plethopcltis armatm , (Billings). The type. Natural size. 
“ 19. Lloydia sp, ind. Thorax and pygidium. Natural size. 
“ 20, Platycolpus capax, (Billings). A cranidium. Natural size. 
* 21. The same species. A pygidium. Natural size. 
