PLATE XXVII 



PLEURODICTYUM LENTICULARE Hall (Pages 422-425) 



Figure 1 . — Lower side of initial cell, or nepionio stage, x 3^. 



Figure 2. — Lower side of initial cell with one bud ; first neanie 

 stage. X 3^. 



Figure S. — Initial cell with two buds ; second neanie stage. X 3^. 



Figure 4. — Initial cell with three buds ; third neanie stage. X 3^. 



Figure o. — Initial cell with four buds; fourth neanie stage. X 3^. 



Figure 6. — Completed neanie stage; showing initial corallite (1) 

 and seven peripheral corallites (2-8). X 3 J. 



Figure 7. — Interior of nepionic corallite. X 3}. 



Figure 8. — Exterior of same specimen. X 3|. 



Figure 9. — Upper side of specimen representing first neanie or 

 ^uZopora stage; consisting of nepionic cell and one bud. Apex of bud 

 opens into visceral cavity of parent cell. X 3^. 



Figure 10. — Profile of same; showing oblique apertures of corallites, 

 and thickened margin of parent cell. X 3^. 



Figure 11. — Lower side of preceding. X 3^. 



Figure 12. — Upper side of completed neanie stage; showing incep- 

 tion of eighth cell. X 3^. 



Figures 1-6 are taken from epitheoal lines of growth shown in Plate 

 XXVIII, figure 2. Remaining figures are from actual specimens. 

 Numbers refer to order of calical succession. 



Lower Helderberg Group, Albany county. New York. 



