PLATE VIII. 



PAGE. 



Fig. 1. Stictopora acuta, Hall.— Fragment of the natural size, . .168 

 la. Surface of same, enlarged to 18 diameters. « 

 16. Tangential section of this species, enlarged to 18 diameters. 

 Fig. 2. Stictopora gilberti, Meek. — A fragment of this species, from the 



Falls of the Ohio; natural size, 168 



2a. Surface of same, enlarged to 18 diameters. 

 Fig. 3. Cystodictya ocellata, n. sp.— Natural size, view of the type speci- 

 men, . . . . . . . 170 



3a. Surface of same, enlarged 18 diameters ; shows the transverse furrows 

 and opercula. 



Fig. 4. Stictopora basalis, n. sp. — A nearly perfect example of this spe- 

 cies ; natural size, 169 



4a. Surface of same, enlarged 18 diameters. 

 Fig. 5. Graptodictya perelegans, Ulrich. — Surface of this species en- 

 larged to 18 diameters, 165 



Fig. 6. Ehinidictya NlCHOLSONl, n. sp. — This figure represents the specimen 



somewhat narrower than it really is, 170 



6a. Surface of same, enlarged to 18 diameters. 

 66. Tangential section of this species, similarly enlarged. 

 Fig. 7. Ph^xopora (?) MULTIPORA, Hall. — Natural size, view of a specimen, 



giving a good idea of the growth of this species, .... 171 

 7a. Surface of sain 2, enlarged to 18 diameters. 

 76. Tangential section, similarly enlarged. 

 Fig. 8. Ph^xopora (?) FENESTELLIFORMIS, Nicholson.— A transverse section 

 of this species, magnified 18 diameters; shows the perforated 



median laminae, 



Fig. 9. Stictoporella ixterstixcta, n. sp. — Represents a fragment of this 



species; natural size, 169 



9a. Surface of same, enlarged to 18 diameters. 

 Fig. 10. Pachydictya robusta, n. sp. — Natural size, view of a rather small 



specimen of this species, ......... 173 



10a. Surface magnified 18 diameters. 



106. Tangential section, enlarged to 18 diameters, showing the cells as 



cut near the median lamina?. 

 10c. Tangential section, showing the structure of the cells and interstitial 



spaces just below the surface; magnified 18 diameters. 

 Fig. 11. Phyllodictya frondosa, n. sp. — A nearly perfect specimen of this 



species ; natural size, 174 



11a. Surface of a well-preserved example, enlarged to 18 diameters. 



116. Tangential section. [Other sections, prepared since the figure was 



engraved, show distinctly numerous minute dots in the interstitial 



spaces. These were not represented in the figure, because they 



were scarcely preserved in the original sections.] 



