PLATE III. 



Fig. 1. — Hermatostroma Schliiteri, n. sp. ; tangential section enlarged 12 times. 

 Devonian, Hebborn (Paffratk district). 



Fig. 2. — Vertical section of the same, similarly enlarged. In both these sections 

 we see the wide axial canals of the radial pillars, and the extensions of these canals 

 into the horizontal connecting-processes by which the concentric laminae are con- 

 stituted. The entire canal-system is injected with some opaque material, probably 

 oxide of iron. 



Fig. 3. — One of the astrorhizse of Stromatopora discoidea, Lonsd., enlarged 

 6 times. "Wenlock Limestone, Wisby, Gotland. 



Fig. 4. — Stromatopora (Stachyodes ?) polyostiolata, Barg., of the natural size. 

 Middle Devonian, Eifel. The specimen shows nipple-shaped prominences, at the 

 summits of which are placed the surface-openings of a system of large canals, 

 which traverse the skeleton at regular intervals, and which represent either the 

 axial tubes of a Stachyodes or the central canals of the astrorhizal systems. [This 

 figure is copied from Goldfuss (' Petref . Germ.,' pi. lxiv, fig. 8,/), and represents 

 one of the forms which he included under the name of S. polymorpha.'] 



Fig. 5. — Stromatopora concentrica, Goldf. var. colliculata, Nich. A broken 

 specimen, of the natural size. Middle Devonian, Gerolstein. The prominent 

 monticules on the surface correspond in general with the axes of the astrorhizae. 



Fig. 6. — Stromatoporella ? incrustans, Hall and Whitf. sp. ; portion of the sur- 

 face, showing the openings of the astrorhizse on prominent chimney-like elevations. 

 Devonian Formation, Iowa. [Copied from Hall and Whitfield, ' Twenty-third 

 Ann. Rep. on the State Cabinet,' pi. ix, fig. 3.] 



Fig. 7. — Labechia conferta, Lonsd. ; under side of a large specimen, of the 

 natural size, showing the concentrically- wrinkled epitheca. Wenlock Limestone, 

 Benthall. 



Fig. 8. — A small example of L. conferta, from the Wenlock Limestone of Got- 

 land, of the natural size. 



Fig. 9. —Under surface of a very young example of L. conferta, Lonsd. (Labechia, 

 n. sp. ?), of the natural size. Wenlock Limestone, Dudley. 



Fig. 10. — Upper surface of the same, nat. size. 



Fig. 11. — Profile of the same. 



Fig. 12. — Surface of Labechia conferta, Lonsd., showing the upward termina- 

 tion of the radial pillars in round tubercles. Enlarged. 



Fig. 13. — Surface of another specimen, in which the tubercles are largely 

 confluent. Enlarged. 



Fig. 14. — A few tubercles of L. conferta, Lonsd., enlarged, showing apparent 

 perforations at their summits. 



Fig. 15. — Completely imperforate and confluent tubercle of young Labechia 

 (Fig. 9). Enlarged. 



