PLATE XXVII. 
Thamniscus dichotomus (Hall). (Page 54.) 
[See also PI. XVIII. figs. 17-10.] 
Fig. 1. Surface view of a young example, X 20, showing the separating ridges. 
2. Portion of the surface of a more mature example, X 20, in which the ridges are less 
marked and the granules more pronounced. 
3. View of the noncelluliferous side of a young example, X 20, in which the char- 
acteristic granulose striae are well exhibited. 
4. Celluliferous and noncelluliferous faces of two zoaria, natural size, exhibiting the 
characteristic diehotomous branching. 
5. Tangential section, X 20, passing close to the surface of the celluliferous side. 
6, 7. Two vertical sections, X 20. 
Rochester shale, Grimsby, Ontario. 
Phocnopora ensiformis Hall. (Page 55.) 
8,9. Tangential and vertical sections, respectively, X 20, showing the internal structure. 
Rochester shale, Grimsby, Ontario. 
Tseniodictya schucherti n. sp. (Page 57.) 
10. Vertical section, X 20. 
11. Tangential section, X 20, in which the zooecia have thickened walls and are 
arranged less regularly than usual. 
12. Portion of tangential section, X 20, showing the usual arrangement of the zooecia. 
13. Outline sketch, natural size, of the type of the species. 
Rochester shale, Grimsby, Ontario. 
Trematopora spiculata Hall. (Page 45.) 
14, 15. Tangential and vertical sections, respectively, X 20. 
Rochester shale, Loekport, N. Y. 
Trematopora whitjieldi Ulrich. (Page 44.) 
[See also PI. XXIII, figs. 16, 17.] 
16, 17. Vertical and tangential sections, X 20. 
Waldron shale, Waldron, Ind. 
Lioclema, globulare n. sp. (Page 35.) 
18. Vertical section, X 20, showing the absence of diaphragms in the zooecia, and the 
irregular tabulation of the mesopores. 
19. Tangential section, X 20, exhibiting the thin-walled zooecia and few acanthopores. 
R hester shale, Loekport, N. Y. 
Lioclema multiporum n. sp. (Page 34.) 
[See also PI. XI, figs. 4-0; PI. XXIII, fig. 18.] 
20. A vertical section, X 20, of the subramose form. 
Rochester shale, Rochester, N. Y. 
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