PLATE XLII 



PAGE 



Figs. 1-4. STROMATOTRYPA GLOBULARIS n. sp 279 



1, 2. Two vertical sections, X 10, one showing the usual features and 

 the second illustrating the closing of a mesopore as the surface 

 is approached. 



3. A tangential section, X 20, with rounded zocecia and rather numer- 



ous acanthopores and mesopores. 



4. A few zocecia, X 20, of a tangential section in which mesopores are 



few. 

 Helderberg formation, Keyser member, Keyser, W. Va. 



Figs. 5-9. CYPHOTRYPA CORRUGATA (Weller) 269 



5. Tangential section, X 20, showing the simple polygonal zocecia. 



6. 7. Several zocecia of the same section, X 50, illustrating the minute 



structure of the walls and acanthopores. 



8. A vertical section through an immature and mature zone, X 20. 



9. Surface of a zoarium, X 9. 



Helderberg formation, Keyser member, Keyser, W. Va. 



Fig. 10. PTILODICTYA TENEIXA n. sp 288 



Tangential section, X 20, illustrating the shape of the zocecia and 

 showing also the inferior hemiseptum as a sharp transverse 

 line in most of the zocecia. Helderberg formation, Keyser 

 member, Devil's Backbone. 



Figs. 11-16. STENOPORA ? INCRUSTANS n. sp 275 



11, 12. Tangential sections, X 20, showing slight variations in the 



wall structure. 

 13, 14. Several zocecia in thin sections, X 50, illustrating the structure 



of the acanthopores and the minute dotting of the walls. 



15. Vertical section, X 20, through a single layer of zocecia. 



16. Surface of a specimen, X 20. 



Helderberg formation, Keyser member, Cash Valley. 



