117 
Idiotrypa punctata (Hall). (Page 40.) 
[See also PL XVII, figs. 4-10.] 
17. View of Hall's type, natural size, growing about a crinoid column. 
18. Surface of same, enlarged. 
19. View of a transverse section of the type. 
Rochester shale, Lockport, N. Y. 
Eridotrypa solida (Hall). (Page 30.) 
[See also PL XII, figs. 7-9; PI. XXV, fig. 16,] 
20. A small fragment, natural size. 
22,23. Three, views of the surface of a zoarium, enlarged. 
Rochester shale, Lockport, N. Y. 
Ptiloporella nervata (Nicholson). (Page 51.) 
[See also PL XXVI, figs. 5, 6.] 
24, 25. Natural size and enlarged views of the noncelluliferous face. (After Nicholson, 
Geol. Survey Ohio, Pal. II, PL XXV, figs. 11.11a. 
Niagara limestone, Cedarville, Ohio. 
Stictotrypa punctipora (Hall). (Page 61.) 
[See also PL XXII, figs. 7-11.] 
26, 27. Natural size and enlarged views of a fragment showing the arrangement and 
shape of the zocecia. 
Rochester shale, Lockport, N. Y. 
Diamesopora dichotoma (Hall). (Page 62.) 
[See also PL XXI, figs. 12. 13.] 
28. Fragment of a zoarium showing the characteristic hollow stems. 
29, 30. Two views of the surface, enlarged. 
Rochester shale, Lockport, N. Y. 
